Patent ID: 8431290
Filing Date: 2013-04-30
Classification: G03F

Abstract:
1. A photomask blank for use in manufacturing a photomask adapted to be applied with exposure light having a wavelength of 200 nm or less, wherein the photomask blank comprises a light-transmitting substrate and a light-shielding film formed on the light-transmitting substrate, the light-shielding film comprises a light-shielding layer containing a transition metal and silicon, and a front-surface antireflection layer formed above and in contact with the light-shielding layer and made of a material containing at least one of oxygen and nitrogen, the light-shielding film has a front-surface reflectance of a predetermined value or less for the exposure light and has a property capable of controlling a change width of the front-surface reflectance at the exposure wavelength to be within 2% when a thickness of the front-surface antireflection layer is changed in a range of 2 nm, and the front-surface antireflection layer is made of the material having a refractive index n and an extinction coefficient k which can achieve the property.