Reflective photomask and production method therefor
A reflective photomask includes: a substrate; a multilayer reflection film formed on the substrate and reflecting exposure light including light with a wavelength of about 5 nm to 15 nm for lithography; an absorption film formed on the multilayer reflection film and absorbing the exposure light, and formed therein with a circuit pattern or a circuit pattern forming region where the circuit pattern is formed; a shading region formed by removing part of the multilayer reflection film and the absorption film on the substrate, on an outer peripheral side of the circuit pattern or the circuit pattern forming region to shade part of the exposure light reflected by the multilayer reflection film; and a plurality of projections formed at a pitch of about 3000 nm or less on part of a surface of the substrate exposed in the shading region, and suppressing reflection of out-of-band light with a wavelength of about 140 nm to 800 nm included in the exposure light and incident on the shading region.
1. A reflective photomask comprising:
a substrate;
a multilayer reflection film formed on the substrate and reflecting exposure light including light with a wavelength of about 5 nm to 15 nm for lithography;
an absorption film formed on the multilayer reflection film and absorbing the exposure light, and formed therein with one of a circuit pattern and a circuit pattern forming region where the circuit pattern is formed;
a shading region formed by removing part of the multilayer reflection film and the absorption film on the substrate, on an outer peripheral side of one of the circuit pattern and the circuit pattern forming region to shade part of the exposure light reflected by the multilayer reflection film; and
a plurality of projections formed at a pitch of about 3000 nm or less on part of a surface of the substrate exposed in the shading region, for suppressing reflection of out-of-band light with a wavelength of about 140 nm to 800 nm included in the exposure light and incident on the shading region.
2. The reflective photomask according to claim 1 , characterized in that the projections are formed so as to have a diameter increased from the absorption film side toward the substrate.
3. The reflective photomask according to claim 1 , characterized in that the projections each have a side face that is a curved face.
4. The reflective photomask according to claim 2 , characterized in that the projections each have a side face that is a curved face.
5. A method for manufacturing a reflective photomask characterized in that the method comprises:
a step of laminating a multilayer reflection film on a substrate to reflect exposure light including light with a wavelength of about 5 nm to 15 nm for lithography;
a step of laminating an absorption film on the laminated multilayer reflection film, the absorption film absorbing the exposure light and being formed therein with one of a circuit pattern and a circuit pattern forming region the circuit pattern is formed;
a step of forming a shading region on an outer peripheral side of one of the circuit pattern and the circuit pattern forming region by removing part of the absorption film and the multilayer reflection film on the substrate, the shading region shading part of the exposure light reflected by the multilayer reflection film; and
a step of forming a plurality of projections on part of a surface of the substrate exposed in the formed shading region, the projections suppressing reflection of out-of-band light included in the exposure light and having a wavelength of about 140 nm to 800 nm.
6. The method for manufacturing a reflective photomask according to claim 4 , characterized in that the step of forming the shading region is integrally performed with the step of forming the plurality of projections to expose the surface of the substrate simultaneously with the formation of the projections.