Patent ID: 8003284
Filing Date: 2011-08-23
Classification: G03F,Y10T

Abstract:
1. A photomask comprising a transparent substrate and a mask pattern formed thereon, said mask pattern comprising transparent regions, phase shift regions and light-shielding regions, and said mask pattern comprising an etch stop film disposed on the substrate with another film intervening therebetween, said etch stop film of single layer or multilayer construction being resistant to fluorine dry etching and removable by chlorine dry etching, said another film comprising a halftone phase shift film, a light-shielding film disposed contiguous to said etch stop film and consisting of a single layer or multiple layers composed of a material containing a transition metal and silicon, and an antireflective film disposed contiguous to said light-shielding film and consisting of a single layer or multiple layers, wherein said transition metal is at least one element selected from the group consisting of titanium, vanadium, cobalt, nickel, zirconium, niobium, molybdenum, hafnium, tantalum, and tungsten, and an optical density OD of the combination of phase shift film, etch stop film, light-shielding film and antireflective film is at least 2.5.