A process for selectively etching silicon comprises preparing a solution of etchant which is a non-selective etch for at least silicon and aluminum. The prepared solution is preconditioned by adding atomic silicon to the solution and aging the solution after the addition of silicon for at least 30 minutes. Then, silicon substrates carrying aluminum are immersed in the preconditioned solution to etch the silicon while leaving the aluminum substantially unaffected.
Iowa State University Research Foundation, Inc.
Braymen, Steven D., "Selective etching process" (1994). Iowa State University Patents. 60.