A method of manufacturing a plurality of through-holes (132) in a layer of material by subjecting the layer to directional dry etching to provide through-holes (132) in the layer of material; For batch-wise production, the method comprises - after a step of providing a layer of first material (220) on base material and before the step of directional dry etching, providing a plurality of holes at the central locations of pits (210), - etching base material at the central locations of the pits (210) so as to form a cavity (280) with an aperture (281), - depositing a second layer of material (240) on the base material in the cavity (280), and - subjecting the second layer of material (240) in the cavity (280) to said step of directional dry etching using the aperture (281) as the opening (141) of a shadow mask