| abstract |
Etching is carried out with an etchant that reacts with a metal to be etched to form an insoluble compound. After the etching using the above etchant, etching is carried out using an etchant that does not form an insoluble compound through a reaction with the metal to be etched, whereby the form of an etched portion comes close to a rectangular form, and the side surface of a conductor pattern becomes smooth. Further, after the etching of one surface of a material to be etched is carried out using an etchant that reacts with a metal to be etched to form an insoluble compound nearly from below, the upper and lower sides of the material to be etched is reversed, and the etching of the opposite surface is carried out nearly from below, whereby fine conductor patterns can be formed on both of the surfaces. |