Characterization of the anisotropic chemical attack of ( h h l ) silicon plates in a TMAH 25 wt.% solution: micromachining and adequacy of the dissolution slowness surface

This paper is devoted to the study of the wet micromachining of 3D silicon structures in a water–TMAH 25 wt.%. In the first part emphasis is placed on changes in shapes with orientation for membranes and mesa etched on various ( h h l ) planes. The observed anisotropy of type 1 agrees with previous conclusions. So, in the second part a previously proposed database is used to derive theoretical 3D etching shapes from the simulator TENSOSIM. Experimental and theoretical 3D etching shapes are analysed by combining dissolution criteria and stereographic projections of limiting facets. Finally we draw some conclusions on the adequacy of the dissolution slowness surface and suggest future possible adjustments.