Method of providing a plurality of through-holes in a layer of structural material

A method of providing a MEMS device comprising a through-hole in a layer of structural material using MEMS method steps, wherein an intermediate product is subjected to a plurality of MEMS method steps, the intermediate product defining a first main side and a second main side, and at least initially comprising a substrate body having a recess at the first main side, the recess comprising a bottom section and a top section, wherein the bottom section is a section of the recess that is closest to the second main side and the top section is a section of the recess that is closest to the first main side;

• wherein the method steps comprise the steps of:
• providing the first main side of the intermediate substrate with a polymeric layer of positive photoresist, said polymeric layer having an outer surface facing away from the body and an inner surface facing the body,
• exposing the polymeric layer of positive photoresist in a direction from the outer surface of the positive photoresist towards the body of the intermediate substrate to light resulting in an exposed layer of positive photoresist comprising:
• a depolymerized positive photoresist in the top section of the recess while leaving a depolymerized positive photoresist in the bottom section of the recess that is less strongly depolymerized than the depolymerized positive photoresist in the top section of the recess;
• removing the depolymerized positive photoresist in the top section of the recess while leaving the less strongly depolymerized positive photoresist in the bottom section of the recess of the body so as to provide a protected area;
• providing structural material at the first main side and outside the protected area;
• and
• etching at the protected area to provide the through-hole in the structural material.