A method of providing a mems device comprising a pyramidal protrusion, and a mold

A method of providing a MEMS device comprising a three-sided pyramidal protrusion using a multitude of MEMS method steps;

• wherein a mold is used, said mold
• defining a first side and a second side,
• comprising a base substrate, wherein at the first side of the mold the surface of the base substrate defines a main plane parallel with the first side, said main plane defining a <111> plane of monocrystalline silicon,
• comprising a sacrificial layer on top of the base substrate at the first side of the mold, said sacrificial layer being chosen from polycrystalline silicon and amorphous silicon;
• comprising a pit at the first side of the mold, said pit;
• extending through the sacrificial layer [from page 3 lines 18-19 of the application as filed] into the base substrate, and
• comprising three wall sections parallel with <111> crystal planes, each of the three wall sections intersecting the other two wall sections, and
• comprising a vertex of a bottom section of the pit;
• wherein the method of providing the MEMS device comprises
• providing an area at the first side of the mold which area extends from a first subarea outside the pit to a second subarea that comprises the vertex of the pit with a layer of protrusion material,
• patterning the layer of protrusion material to the desired shape, and
• isotropically etching the sacrificial layer of the mold with an isotropic etchant capable of etching the sacrificial layer so as to separate the MEMS device from at least the base substrate of the mold.