Patent attributes
An antireflection film wherein, even where exposure light enters obliquely in a liquid immersion lithography technique, a sufficiently reduced reflectance can be achieved at the interface between a resist layer and a silicon substrate. A two-layer antireflection film is used in exposure by an exposure system having a wavelength of 190 to 195 nm and a numerical aperture of 1.0 or less and formed between the resist layer and the silicon substrate. Where complex refractive indices N1 and N2 and film thicknesses of upper and lower layers of the antireflection film are represented by n1-k1i, n2-k2i and d1, d2, respectively, and a predetermined combination of values of [n10, k10, d10, n20, k20, d20] is selected, n1, k1, d1, n2, k2 and d2 satisfy {(n1-n10)/(n1m-n10)}2+{(k1-k10)/(k1m-k10)}2+{(d1-d10)/(d1m-d10)}2+{(n2-n20)/(n2m-n20)}2+{(k2-k20)/(k2m-k20)}2+{(d2-d20)/(d2m-d20)}2≦1.
