Mask blank glass substrate
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsNaoki Yarita, Daijitsu Harada, Masaki Takeuchi
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Abstract
A mask blank glass substrate having a maximum value of a circularly averaged power spectral density of 1,000 nm4 or less at a spatial frequency of 0.1 μm−1 or more and 20 μm−1 or less, the maximum value being obtained by measuring a surface morphology of a region of 10 μm×10 μm with an atomic force microscope.
Claims10
A mask blank for extreme ultra violet lithography (EUVL) comprising a glass substrate having a maximum value of a circularly averaged power spectral density of 1,000 nm4 or less at a spatial frequency of 0.1 μm−1 or more and 20 μm−1 or less, the maximum value being obtained by measuring a surface morphology of a region of 10 μm×10 μm with an atomic force microscope and a multilayer reflective film laminated on the glass substrate.
Dependencies are inferred from the claim text.