Among the silicon anisotropic etchants, tetramethyl ammonium hydroxide [TMAH] is of great interest due to the absence of metal ions. Therefore using TMAH solutions at low concentrations has the advantage of being more economical, both in terms of cost and time. Unfortunately the surface quality of the etched <100> silicon is strongly influenced by the concentration of the solution i.e. at low concentrations (less than 15%), the etched surfaces are very often covered with pyramidal-shaped hillocks, thus producing a very rough surface finish. Ammonium Persulfate (NH4)2S2O8 can be added to TMAH to suppress hillock formation. We investigated the effects of this additive under different oxidizer addition conditions. The influence of TMAH concentration and etchant temperature was evaluated.
Characterization of TMAH Silicon Etchant Using Ammomium Persulfate as an Oxidizing Agent
Guarnieri, Vittorio;Giacomozzi, Flavio;Zen, Mario
1998-01-01
Abstract
Among the silicon anisotropic etchants, tetramethyl ammonium hydroxide [TMAH] is of great interest due to the absence of metal ions. Therefore using TMAH solutions at low concentrations has the advantage of being more economical, both in terms of cost and time. Unfortunately the surface quality of the etched <100> silicon is strongly influenced by the concentration of the solution i.e. at low concentrations (less than 15%), the etched surfaces are very often covered with pyramidal-shaped hillocks, thus producing a very rough surface finish. Ammonium Persulfate (NH4)2S2O8 can be added to TMAH to suppress hillock formation. We investigated the effects of this additive under different oxidizer addition conditions. The influence of TMAH concentration and etchant temperature was evaluated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
