PURPOSE: To improve the accuracy of mask patterns by simultaneously sputtering material pieces contg. silicon as well to form a chromium film or chromium oxide film contg. silicon particles on a mask substrate at the time of sputtering chromium or chromium oxide.

CONSTITUTION: The material pieces contg. the silicon are simultaneously sputtered as well to incorporate the silicon particles into the chromium film 7 or the chromium oxide film 6 at the time of forming the chromium film 7 as a light shielding film or the chromium oxide film 6 as an antireflection film on the mask substrate 5. The silicon particles are incorporated at a relatively uniform density into the chromium film 7 or the chromium oxide film 6. The force acting among the crystal particles of the formed chromium film 7 or the chromium oxide film 6 is accordingly uniformly adjusted by interposing the silicon particles and, therefore, the internal stresses of these films are uniformly adjusted. Thus, the stresses and strains between these masks and the mask substrate 5 are uniformly decreased and the accuracy of the mask pattern is improved.