REFLECTIVE MASK BLANK FOR EUV LITHOGRAPHY AND PROCESS FOR ITS PRODUCTION, AS WELL AS SUBSTRATE WITH REFLECTIVE LAYER FOR SUCH MASK BLANK AND PROCESS FOR ITS PRODUCTION

摘要

To provide a mask blank for EUVL excellent in in-plane uniformity of the peak reflectivity of light in the EUV wavelength region and in in-plane uniformity of the center wavelength of reflected light in the EUV wavelength region, at the surface of a multilayer reflective film, and a process for its production, as well as a substrate with reflective layer for EUVL to be used for the production of such a mask blank for EUVL, and a process for its production.;A substrate with reflective layer for EUV lithography (EUVL) having a reflective layer for reflecting EUV light formed on a substrate,
wherein the reflective layer is a multilayer reflective film having a low refractive index layer and a high refractive index layer alternately stacked plural times,among the respective layers constituting the multilayer reflective film, at least one layer of at least one pair of adjacent low refractive index layer and high refractive index layer is made to be a reflectivity distribution correction layer, andthe reflectivity distribution correction layer has a thickness distribution which satisfies the following formula (1) in a radial direction from the center of the substrate:;−0.011x2+0.1x+100−α≦y≦−0.011x2+0.1x+100+α  (1);wherein x is a location in a radial direction from the center of the substrate represented by the relative value where the center of the film-forming surface on the substrate on which the reflective layer is to be formed, is 0%, and the outer edge at the reflectivity measurement position farthest from the center of the film-forming surface, is 100%; y is the amount of change of the thickness of the reflectivity distribution correction layer represented by the rate of change where the minimum value of the thickness of the reflectivity distribution correction layer is 0%, and the maximum value of the thickness of the reflectivity distribution correction layer is 100%; and α is 25.

主权项

1. A substrate with reflective layer for EUV lithography (EUVL) having a reflective layer for reflecting EUV light formed on a substrate,
wherein the reflective layer is a multilayer reflective film having a low refractive index layer and a high refractive index layer alternately stacked plural times, among the respective layers constituting the multilayer reflective film, at least one layer of at least one pair of adjacent low refractive index layer and high refractive index layer is made to be a reflectivity distribution correction layer, and the reflectivity distribution correction layer has a thickness distribution which satisfies the following formula (1) in a radial direction from the center of the substrate:
−0.011x2+0.1x−100−α≦y≦−0.011x2+0.1x+100+α  (1)wherein x is a location in a radial direction from the center of the substrate represented by the relative value where the center of the film-forming surface on the substrate on which the reflective layer is to be formed, is 0%, and the outer edge at the reflectivity measurement position farthest from the center of the film-forming surface, is 100%; y is the amount of change of the thickness of the reflectivity distribution correction layer represented by the rate of change where the minimum value of the thickness of the reflectivity distribution correction layer is 0%, and the maximum value of the thickness of the reflectivity distribution correction layer is 100%; and α is 25.