Mask blank, transfer mask, and film denseness evaluation method
AssigneeHoya Corporation
InventorsOsamu Nozawa, Kazuya Sakai
Life of this patent
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Abstract
A relative density of a light-shielding film made of MoSi, which is given by relative density=(actual density/theoretical density)×100, is obtained using a density (actual density) calculated by an XRR method and a theoretical density obtained from a material composition. By obtaining a dense film having a relative density greater than 94%, the thickness of an alterated layer, caused by exposure light, at a surface of the MoSi film can be made not more than 2.0 nm so that the dimensional change of a transfer pattern can be made small.
Claims14
A mask blank for use in the manufacture of a transfer mask adapted to be applied with ArF exposure light, the mask blank having a thin film for forming a transfer pattern on a transparent substrate,
- wherein the thin film is made of a material containing tantalum (Ta), and
- when an actual density of the thin film is given by d1 and a theoretical density calculated from a film composition of the thin film is given by d2, a relative density d of the thin film given by d=(d1/d2)×100 is greater than 83%.
A mask blank for use in the manufacture of a transfer mask adapted to be applied with ArF exposure light, the mask blank having a thin film for forming a transfer pattern on a transparent substrate,
- wherein the thin film is made of a material containing silicon (Si) and a transition metal, and
- when an actual density of the thin film is given by d1 and a theoretical density calculated from a film composition of the thin film is given by d2, a relative density d of the thin film given by d=(d1/d2)×100 is greater than 94%.
A film denseness evaluation method for evaluating a denseness of a thin film of a mask blank having the thin film on a transparent substrate, which comprises
- setting an actual density of the thin film to d1,
- analyzing a material composition of the thin film,
- setting a theoretical density calculated from the material composition of the thin film to d2,
- calculating a relative density d from the actual density d1 and the theoretical density d2 according to d=(d1/d2)×100, and
- evaluating the denseness of the thin film by the relative density d.
Dependencies are inferred from the claim text.