| 摘要 |
PURPOSE:To eliminate the waste of noble metal and to decrease considerably the generation of a bend in leads by plating with noble metal on a raw material in the form of a thin plate or rod and blanking out an unnecessary part in the final stage. CONSTITUTION:A photoresist 7 is coated over the entire surface of a raw material 6 such as a thin plate or rod of iron, iron alloy, copper or copper alloy in the stage of producing a lead frame plated with a noble metal only on the top surface part at, for example, the top end of leads. Only the part 8 to be plated with the nobel metal at the top end of the leads is exposed to expose the material 6. Said material is processed with a plating device to electrodeposit a noble metal 9 only on the exposed part of the material 6. Both surfaces are then exposed by using a photomask having a lead frame pattern and are exposed to expose the raw material between the leads and between the leads and island 10. When such material is etched, the material 6 is successively etched from the exposed parts 10 on the both surfaces toward the inside until the material is penetrated. The remaining nonexposed photoresist is stripped away. |
