| 摘要 |
PURPOSE:To raise connection reliability by smoothening an inner wall shape of a hole and besides, to enable working to be effectively performed for a short time by a method wherein a hole to be worked is etched with etching liquid containing excitation species of gas containing fluorine or a fluorine compound. CONSTITUTION:A substrate 8 is composed of a copper foil 1, epoxy resin 2, and glass woven cloth 3. Counter electrodes 7 are established in a container 6 and the substrate 8 is fixed to its one side. After making a specific pressure by introducing gas of, for example, tetrafluoride carbon or the like into the container 6 from a gas introducing tube 9, discharge is generated between the electrodes 7, and an inner wall shape of a hole to be worked of the substrate 8 is smoothened with excitation species of generated gas. Thus glass fiber 5 protruded to the inner wall before smoothening process is removed by treatment and further, burrs 4 also are removed. As gas containing fluorine, there are, other than tetrafluoride carbon, hydrogen fluoride, hexafluoroethane, perfluoropropane, perfluorobutane, trifluoromethene etc. Gases of hydrogen, oxygen, hydrocarbon, etc. are mixed with those gases to be preferably used. |
