| 摘要 |
PURPOSE:To simplify the working operation of the title device and to increase the reliability of an electric connection via a via hole by a method wherein the via hole is filled substantially with a solder by heating and melting a solder ball or a solder wire. CONSTITUTION:A copper-foil sheet 1 is pasted; by using an epoxy-based adhesive 27 on an insulating layer (a polyimide) 3 in which a via hole has been formed. Then, a solder (80% Sn-20% Pb alloy) wire is inserted into the via hole; it is cut; after that it is heated at about 210 deg.C. Then, a copper layer 11 is formed by a vacuum evaporation method, on the surface of the insulating layer 3 and a solder layer 10; after that, a resist-coating operation, a patterning operation and the etching operation of the copper layer are executed; the two-layer structure of a fine interconnection is formed. Thereby, a solder ball or the solder wire is filled into the via hole. Thereby, since a first conductive layer can be connected to a second conductive layer via the via hole, the reliability of the title device against a thermal stress is enhanced. |
