| 摘要 |
PURPOSE:To effectively partly plate at the end of a lead frame by forming the sectional shape in the vicinity of the end of the lead frame nearly in trapezoidal shape. CONSTITUTION:A vinyl chloride mask 25 is covered on a main surface 221 except the partly plated part 23 of a lead frame 20, an Si rubber plate 26 is placed on the other main surface 222, and is pressed through a plate 27. At this time the rubber 26 is contacted intimately with the side surface of each lead pin, and is partly projected from the main surface 221. When it is plated in this state and the prescribed part is partly plated at the part 23, an excessively plated part is not produced at all, and even if mechanical or thermal impact is applied to the pins 22, a shortcircuit accident due to the excessively plated part can be avoided between the pins, thereby obtaining a lead frame having pre ferable characteristics. When photomasks of different shape and size are formed on the main surfaces 221, 222 and are etched, a lead pin of sectional shape of nearly trapezoidal shape having an oblique surface 24 can be obtained. |
