| 摘要 |
PURPOSE: To provide the manufacturing method of a lead frame wherein process control is easy, and therefore quality stability and cost reduction are excellent. CONSTITUTION: A lead frame is formed by using three-layered clad material 20 which consists of a planar metal base 21 turning to an outer lead forming part member, an etching stopper layer 22 formed on one surface of the metal base 21, and a chromium layer 23 formed on the etching stopper layer 22. The manufacturing method of the lead frame consists of the following; a process which forms a plating resist layer on the chromium layer 23, a process which forms inner leads 24 by using the plating resist layer as a mask and plating copper on the chromium layer 23, a process which forms outer leads 25 in the regions of the metal base 21 where the outer leads are arranged, a process which eliminates, by etching, the rear of the region of the metal base 21 where the inner leads are arranged, a process which etches the etching stopper layer 22, and a process for eliminating the chromium layer 23. |
