| 摘要 |
<p>PURPOSE:To ensure insulation between inner leads by coating the side face of the inner lead with an insulator and applying metal plating only on the upper face of the inner lead. CONSTITUTION:Copper foil is applied directly onto a film 10 composed of polyimide and then the copper foil is etched to form a multiplicity of independent conductor circuits 20. The double layer film 10 is then etched with caustic soda, hydrazine, or the like to form an opening 11. An insulator 30, i.e., photosensitive polyimide, is then employed to form a polyimide film between inner leads 21 and on the upper face 21b of the inner lead 21. The polyimide 30 is then removed from the upper face 21b of the inner lead 21 thus exposing the upper face 21b. Thus exposed upper face 21b and the conductor circuit 20, e.g. an outer lead 22 adhered with no insulator 30, are then subjected to tin plating. According to the method, the inner lead is protected against bending or deformation even if it is made fine.</p> |
