| 摘要 |
PURPOSE:To manufacture a lead frame having sufficient flatness efficiently by punching-machining the depressing-machined lead frame from a metallic strip, partially plating it and depressing-machining it at the same time as a sizing cutting process. CONSTITUTION:Lead frames 1', 1, 1'' in a shape having an IC loading section 2 and internal leads 3 are punching-machined continuously. Sections shown in oblique lines in the figure are plated 4 partially, and several lead frame is cut from a metallic strip, from which the lead frames are punched, while they are depressing-machined, thus completing the lead frames. No depressing machining section of the lead frames is deformed in pre-processes, such as punching, partial plating, etc. because said processes are executed at the same time as cutting machining in which depressing machining is conducted finally, and no back and side surface is plated in the chip loading section and the nose sections of the internal leads because even partial plating is conducted in a plate shape. |
