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1990
Journal Article
Titel
Fabrication of non-underetched convex corners in anisotropic etching of 100-silicon in aqueous KOH with respect to novel micromechanic elements
Abstract
The planes occurring at convex corners during anisotropic etching of (100)-silicon in aqueous KOH were identified as (411)-planes with the help of an especially developed measuring technique. The etching rate of these planes in relation to the rate of the (100)-planes declines with increasing potassium hydroxide concentration. In contrast, the temperature dependence of this etch rate ratio is neglectable in the relevant range between 60 degree C and 100 degree C. Based on these results, special structures suited for the compensation of the undercutting in the case of very narrow contures were developed. With the help of these structures it is feasible to realize, for instance, bent V-grooves or structures with a very low ratio between lateral expansion and etching depth, e.g. a descrete pyramid-trunk with minimum dimensions on the wafer surface. This offers access to completely new applications, among others spiral channels with double-sided anisotropic etching for micromechanical heat exchangers, corrugated diaphragms stiffened in two dimensions with low thermal resistance and arbitrary wall thickness, bellow structures for decoupling mechanical stresses between micromechanical devices and their packaging. Furthermore, this technology paves the way for designing novel types of accelerometers and inclination sensors with external seismic mass.
Language
English