| 摘要 |
PURPOSE:To obtain microminiaturization of circuits by combining two separated metallic boards with an insulating film and providing pads only at one side of the metallic boards, thereby enabling a packaging area on the other side of metallic boards to be used in a large way. CONSTITUTION:Metallic boards 11 and 12 are connected with adhesives by means of an insulating film 13 in such a way that there is a distance corresponding to the thickness of each board between respective two boards. Copper foils acting as conductive paths 14 are pasted at the opposite main faces of the film 13 and the conductive paths 14 having desired forms are formed by selective etching. Pads 17 for soldering outer leads 16 are placed at one side end parts of the board 12 and the conductive paths 14 are extended from the pads 17 on the insulating film 13. Parts of the conductive paths 14 which bond circuit elements 15 are designed to locate on both sides of the boards 11 and 12. Then, the circuit elements 15 are selected and they are bonded and mounted on the boards 11 and 12. After providing the pads 17 only at one side of the board 12 and also incorporating the circuit elements 15 on the board 12, the film 13 is bent to make the boards 11 and 12 abut on each other. After that, they are bonded and after leaving the leads 16 as they stand, the whole elements are molded with resin 18. |
