Patent ID: 9366951
Filing Date: 2016-06-14
CPC Classification: G03F

Claim Text:
1. A halftone phase shift photomask blank comprising a transparent substrate and a halftone phase shift film thereon, said halftone phase shift film consisting of silicon and nitrogen, or silicon, nitrogen and oxygen, providing a transmittance of at least 10% and a phase shift of 150° to 200° relative to light of wavelength up to 200 nm, and having a thickness of up to 70 nm, said halftone phase shift film being a single layer consisting of silicon and nitrogen, or silicon, nitrogen and oxygen, with the content of oxygen being up to 1/3 of the content of nitrogen as expressed in atomic ratio, and having a refractive index of at least 2.4 and an absorption coefficient of 0.22 to 0.54, or a multilayer film including at least one layer consisting of silicon and nitrogen, or silicon, nitrogen and oxygen, with the content of oxygen being up to 1/3 of the content of nitrogen as expressed in atomic ratio, and having a refractive index of at least 2.4 and an absorption coefficient of 0.22 to 0.54.