Method of manufacturing a plurality of through-holes in a layer of first material

A method of manufacturing a plurality of through-holes in a layer of first material wherein an intermediate product is subjected to a plurality of method steps, the intermediate product

• defining a first side and a second side, and
• comprises a base substrate, said base substrate comprising a base material, wherein at the first side the surface of the base substrate defines a main plane;
• wherein the plurality of method steps comprises the steps of
• providing the base substrate of the intermediate product at the first side with a plurality of pits in said base material, and
• providing the base substrate with the layer of first material at the first side of the intermediate product, the first material being different from the base material so as to result in the intermediate product having pits comprising a layer of said first material,
• providing a second layer of a second material that is different from the first material on the layer of first material, and
• providing the second layer of the second material with a plurality of holes, the holes being provided at the central locations of the pits, and
• with the second layer of the second material comprising the plurality of holes at central locations of the pits, subjecting part of the layer of said first material to ion beam milling to provide through-holes in the layer of first material by subjecting the first side of the base substrate provided with the second layer of the second material to said step of ion beam milling using said second layer of the second material as a shadow mask by having the ion beam at an angle α to the normal to the base main plane of at least 5°.