US 12,013,415 B2
Method of providing a MEMS device comprising a pyramidal protrusion, and a mold
Edin Sarajlic, Zutphen (NL)
Assigned to SMARTTIP BV, Enschede (NL)
Appl. No. 17/603,226
Filed by SMARTTIP BV, Enschede (NL)
PCT Filed Apr. 7, 2020, PCT No. PCT/NL2020/050237
§ 371(c)(1), (2) Date Oct. 12, 2021,
PCT Pub. No. WO2020/209716, PCT Pub. Date Oct. 15, 2020.
Claims priority of application No. 2022939 (NL), filed on Apr. 12, 2019.
Prior Publication US 2022/0187336 A1, Jun. 16, 2022
Int. Cl. G01Q 70/16 (2010.01); G01Q 70/10 (2010.01)
CPC G01Q 70/10 (2013.01) [G01Q 70/16 (2013.01); B81B 2201/12 (2013.01)] 15 Claims
OG exemplary drawing
 
1. 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 from the first side through a through-opening in the sacrificial layer 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, when seen from the first side and in projection onto a plane substantially parallel to the main plane, the three wall sections are completely visible through the through-opening in the sacrificial layer;
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, such that part of the layer of protrusion material extends through the through-opening,
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.