Fabrication methods

A method of fabricating a pattern on a substrate, the method comprising:

• forming a patterning structure on the substrate, the patterning structure comprising one or more shadow walls extending outwardly from a plane in which a surface of the substrate substantially lies;
• in a first deposition phase, selectively depositing a first layer of material on the surface of the substrate using a first beam;
• and
• in a second deposition phase, selectively depositing a second layer of material on the surface of the substrate using a second beam,
• wherein the first and second beams have a non-zero angle of incidence relative to an axis normal to the surface of the substrate and different azimuthal angles about said axis, such that, in the first deposition phase, the first beam is incident on one side of a shadow wall of the patterning structure whereby the shadow wall prevents deposition in a first exposed shadow region adjacent the opposite side of the shadow wall in the plane of the substrate, and, in the second deposition phase, the second beam is incident on one side of the shadow wall or another shadow wall of the patterning structure whereby that shadow wall prevents deposition in a second exposed shadow region adjacent the opposite side of that shadow wall in the plane of the substrate.