Patent ID: 7592130

Claim:
An exposure method comprising: illuminating a mask that has a contact hole pattern using an illumination light; and projecting, via a projection optical system, the contact hole pattern onto a substrate to be exposed, wherein said contact hole pattern is a checker pattern that includes a plurality of periodic patterns, each of which has plural contact holes arranged in a first direction at a first pitch, and the plurality of periodic patterns are arranged in a second direction perpendicular to the first direction at a second pitch while shifting by half a pitch, wherein an effective light source formed on a pupil plane in the projection optical system by the illumination light has six poles, wherein a distance between centers of the six poles and an optical axis of the projection optical system is commonly a, wherein said centers of the six poles are located around the optical axis in a direction of an angle α to the first direction, wherein said angle α is 0, 2α, π−2α, π, π+2α, and 2π−2α, wherein Pxo/2=(Px/2)NA/λ, Pyo/2=(Py/2)NA/λ, α=tan −1 (Pxo/(2Pyo)), and a =1/(4(Pyo/2)/sin(2α)) are satisfied, where Px is the first pitch, Py is the second pitch, NA is a numerical aperture of the projection optical system, and λ is a wavelength of the illumination light, and wherein three beams among diffracted lights from the contact hole pattern interfere with each other.