Patent ID: 6245213
Filing Date: 2001-06-12
Classification: C23F,C25F,H05K

Abstract:
A method for anisotropic etching of a structure in an electrically conductive substance by means of an etchant which in a first solution at a first concentration and in the absence of an electric field will isotropically etch structures in the substance by spontaneous chemical reaction with the substance, said method comprising the steps of:contacting the substance with a second solution of the etchant which is diluted to a second concentration lower than said first concentration and which will isotropically etch structures in the substance by spontaneous chemical reaction with the substance in the absence of an electric field at a maximum etching rate of 5 nm/s; andsubjecting the second solution adjacent to the area of the substance to be etched to an electric field of such a strength that anisotropic etching of said structure in the substance is accomplished.