Preventing side-etching by adhering an overhang mask to the sidewall with adhesive

Claim 1

A chemical etching method comprising the steps of: forming an etching-resistant mask, having a predetermined pattern, on the surface of a metal member to be etched; subjecting said metal member to a first chemical etching step through said mask; joining those portions of said mask which overhang side-etched portions of said metal member, following said first etching step, to the side walls of the said side-etched portions thereby to form a first etching-resistant layer on said side walls, said joining step comprising applying an adhesive binder solution to parts of said metal member including said side walls and thereafter heating said metal member to dry said adhesive binder solution, the said overhanging portions of said mask being bent down by the surface tension of the adhesive binder solution at the corner between the overhanging portions of said mask and the side walls of said side-etched portions as the adhesive binder solution is dried, the adhesive binder between said first etching-resistant layer and said side walls of said side-etched portions thereafter being hardened to form a second etching-resistant layer which joins said first layer to said side walls; and thereafter subjecting said metal member to a second chemical etching step through said mask and said etching-resistant layers.