US Patent 7745842 Graytone mask and method thereof

A transmissivity controlled film 12 (CrO or the like), a transmissivity reduced film 13 (Cr or the like), and a resist film 14, for instance, are sequentially formed on, e.g., a transparent substrate 11. A resist is removed from an area (an area C) where a light-transmission section is to be formed, and the transmissivity reduced film 13 and the transmissivity controlled film 12 are removed from the area, thereby forming a light-transmission section. Next, a resist is removed from an area (an area A) in which a graytone section is to be formed, thereby removing the transmissivity reduced film 13 from that area, to thereby form a graytone section. Thus, a graytone mask is manufactured.