Grayscale lithography mask

A method for insolating a photosensitive resin comprising the following steps:

• providing a photosensitive resin,
• exposing the photosensitive resin to an insolation radiation having been emitted by a light source having a coherence σ and a numerical aperture NA, the insolation radiation having a wavelength 2,
• developing the photosensitive resin,
• the exposure of the photosensitive resin to the insolation radiation being done through a grayscale lithography mask, extending mainly along a horizontal plane defined by a first direction and a second direction, the horizontal plane being perpendicular to a main direction of the insolation radiation of the photosensitive resin through the mask, the mask comprising a plurality of zones which are opaque to the radiation, the plurality of opaque zones comprising first opaque zones and second opaque zones, the first opaque zones being organised along a pitch array P1 in the horizontal plane and the second opaque zones being organised along a pitch array P2 in the horizontal plane, such that P1<PRayleigh and P2≥PRayleigh, with
• P
• Rayleigh
• =
• 1
• 1
• +
• σ
• *
• λ
• NA
• such that, after the development of the photosensitive resin, the photosensitive resin has a first structuration level and a second structuration level superimposed on one another.