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US 8,263,294 B2Granted
Lithographic mask and manufacturing method thereof
AssigneeHoya Corporation
InventorsJunji Mori, Katsuhiro Takushima
Life of this patent
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Abstract
Cleaning is carried out by using a sulfuric acid type detergent at a resist stripping and cleaning step (step 5) in a semitranslucent portion forming process and a resist stripping and cleaning step (step 10) in a shielding band forming process, and a sulfuric acid removing step of partially or wholly removing a surface layer portion in a pattern into which a sulfate ion is adsorbed is then carried out to effectively remove the adsorbed sulfate ion.
Claims9
A lithographic mask used for exposure light having a wavelength of 200 nm or less, the lithographic mask comprising:
- a transparent substrate;
- a pattern for transfer made of a layer containing nitrogen, said pattern being formed on the transparent substrate, and
- a shielding band which comprises a shielding film formed on the layer in a peripheral portion of a transfer region, said transfer region having said pattern for transfer, wherein the pattern for transfer is subjected to a surface composition reformation in which oxygen concentration is increased so that the formation of ammonium ion on the surface of the layer is prevented, said surface composition reformation being made such that the concentration of NH4+ measured by ion chromatography is 20 ng/cm2 or less.
Dependencies are inferred from the claim text.