| 摘要 |
<p>PURPOSE:To improve the external appearance by removing an oxide film of exposed lead frame, and oxidizing uniformly the exposed lead frame after removing the oxide film, thereby uniforming forming the oxide film without spot. CONSTITUTION:A lead frame 1 completed in the step of molding resin is suspended and supported by a holder 10 with heat sink plates 4, 4... disposed at downside, and the exposed portions of the plates 4, 4... are dipped in an etchant 11. When the oxide film removal at the exposed portion is completed, the frame 1 is filled in an oxide tank 12 immediately thereafter, a cover 13 is put, the interior is filled with oxygen-containing atmosphere and is allowed to stand for the prescribed time. Then, the exposed portions of the plates 4, 4... are simply and effectively uniformly oxidized. When the plates 4, 4... are formed of copper plates, the entire exposed portion is oxidized to be brown to obtain a good external appearance. Thus, the entire plates are uniformly provided with thermal conductivity to improve the heat sink effect.</p> |
