Patent ID: 10935881

Abstract:
An object is to provide a mask blank for manufacturing a phase shift mask in which a thermal expansion of a phase shift pattern, which is caused when exposure light is radiated onto the phase shift pattern, and displacement of the phase shift pattern are suppressed to be small. A phase shift film has a function of transmitting exposure light from an ArF excimer laser at a transmittance of 2% or higher and 30% or lower and a function of generating a phase difference of 150° or larger and 180° or smaller between the exposure light that has been transmitted through the phase shift film and the exposure light that has passed through air by a distance equal to a thickness of the phase shift film. The phase shift film is formed of a material containing a metal and silicon, and has a structure in which a lower layer and an upper layer are laminated in the stated order from a transparent substrate side. The lower layer has a refractive index n at a wavelength of the exposure light that is smaller than that of the transparent substrate. The upper layer has a refractive index n at the wavelength of the exposure light that is larger than that of the transparent substrate. The lower layer has an extinction coefficient k at the wavelength of the exposure light that is larger than that of the upper layer. The upper layer has a thickness that is larger than that of the lower layer.