| 摘要 |
PURPOSE:To miniaturize an inner lead and a bump by a method wherein third metallic layer is formed on the surface of a second metallic layer furthermore, the first metallic layer is patterned and then the second metallic layer is etched away using first and third metallic layers as masks. CONSTITUTION:A first metallic layer 1 and a second metallic layer 2 are laminated on a lead frame material 3. Next, both sides of the lead frame material 3 are coated with photoresist films 4 and then a third metallic layer 6 comprising copper is formed on the exposed part of the second metallic layer 2 by electrolytic plating step. At this time, a photoresist film 7 on the first metallic layer 1 is exposed and developed to be used as a mask for the formation of an outer lead. Next, the first metallic layer 1 is patterned by etching step using the photoresist film 7 as a mask to form the outer lead 3. Finally, the second metallic layer 2 is etched away using the third metallic layer 6 and the first metallic layer 1 as masks so as to form the title lead frame. |
