Patent ID: 6842224

Claim:
An exposure method comprising the steps of: illuminating a mask that forms a contact-hole pattern and auxiliary pattern smaller than the contact-hole pattern with light from a light source: and projecting light from the mask onto an object to be exposed via a projection optical system at least at a position having a distance from a focus position at provides the highest resolution, wherein the distance A meets the following equation: 0< A≦k 1 ×( D/S )×(λ/ NA 2 ) where D is a hole diameter of the contact-hole pattern, S is a hole diameter of the auxiliary pattern, P is a half-pitch of the contact-hole pattern and auxiliary pattern, λ is a wavelength of the light from the light source, NA is a numerical aperture of the projection optical system, and k 1 =(NA/λ)×P.