Abstract: A masking method for controlling the limit of irradiation areas of a photoresist material layer by an irradiation source having a given wavelength, through a mask designed for forming on the photoresist material layer a given image, by means of an optical system having a given resolution limit, comprising the step of forming at the limit between dark and transparent areas of the mask, dark stripes having a chosen width (a) and spaced apart from the limit by a chosen distance (b), the width (a) and the distance (b) being such that the product of their values by the reduction factor of the optical system is lower than the resolution limit.