| 摘要 |
PURPOSE:To form a lead frame having less width camber by feeding a metal strip bar to a progressive die and after punching one part of a lead frame pattern feeding it to the progressive die by turning over the metal strip bar and punching the remaining part of the feeding to the progressive die from the reverse direction. CONSTITUTION:In order to form the lead frame 10 used for a resin sealing type semiconductor device a metal strip bar 11 is first fed to a progressive die to subject the inner pattern part 24 surrounded by a broken line as shown in A on the figure and a guide hole 21 to a pressing. The metal strip bar 11 pressing the inner pattern part 24 is thereafter turned backside out. It is then located with the guide hole 21 formed by pressing as shown by B on the figure as the reference and formed in a specified shape by subjecting an external part lead part 12, damper 22 and rail part 20 excepting the inner pattern part 24 to a pressing. A plating treatment, cutting with bend, etc., are thereafter performed. The width camber due to punching is thus canceled each other.
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