Abstract: In a process for determining the focussing of a photolithographic apparatus on a resist-coated wafer, comprising the following steps: 1) insolating, successively in various places, the resist by a test pattern, a different focussing being carried out for each insolation; 2) developing the resist; 3) observing the wafer for determing the optimal insolation and adopting the corresponding setting for the apparatus, it is provided, between steps 2) and 3), the step consisting in heating the wafer up to a temperature higher than the vitreous transition temperature of the resist.

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.