Patent ID: 7678508
Filing Date: 2010-03-16
Classification: G03F,H01L

Abstract:
1. A method of manufacturing a mask blank used as a material of a pattern transfer mask, having a substrate and a thin film optically relating to a transfer exposure light which is a material of a pattern transfer mask, comprising: forming the thin film on the surface of the substrate; and forming a dust-free protective film which is formed of a material removable by solvent which does not affect the thin film, so that the thin film is covered by the dust-free protective film, wherein an unnecessary part formed on a peripheral edge of the substrate of the dust-free protective film is removed by the solvent, thereby preventing a surface of the mask blank itself from direct adhesion of foreign matters and from thereby being damaged in the subsequent step, and when the pattern transfer mask is manufactured from the mask blank, the dust-free protective film is removed by the solvent before a resist film forming step for forming a resist film on the thin film.