MASK BLANK AND PHOTOMASK

PROBLEM TO BE SOLVED: To provide a mask blank capable of manufacturing a photomask having a structure effectively preventing electrostatic breakdown.SOLUTION: An electrostatic breakdown preventive film 2 is formed to cover the entire surface of one side of a mask substrate 1, and a light-shielding film 3 is formed atop the electrostatic breakdown preventive film 2. A photomask is prepared by patterning the light-shielding film 3. The electrostatic breakdown preventive film 2 is a film consisting of titanium, titanium compound, tantalum, or tantalum compound, exhibiting transmissivities of at least 75% in relation to lights of exposure wavelengths, and bearing a sheet resistance value of 100 K /sq. or below. In a case where the electrostatic breakdown preventive film 2 consists of a titanium compound or tantalum compound, the film is prepared by means of sputtering using a gas obtained by adding, to an argon gas, an oxygen gas and a nitrogen gas or a carbon dioxide gas and a nitrogen gas.