| 摘要 |
PURPOSE:To obtain a highly stable, high quality lead frame having highly accurate sizes, by performing heat treatment under the state internal leads are connected by a linking piece and the accuracy of the sizes is maintained, thereafter removing the linking piece, thereby completely removing internal residual strain. CONSTITUTION:The desired shape of a lead frame is machined by press machining or a chemical etching method, with a linking piece 12, which connects the tips of inner leads 10, being remained. In the Figure, the tips of all the inner leads 10 are connected by the linking piece 12. However, the inner leads 10 are divided into a plurality of groups, and the tips of the inner leads of the groups can be connected by the linking pieces, which are provided in a plurality of pieces. The heat treatment of the lead frame, which is machined in this shape, is performed under the state with the linking piece 12 being remained, i.e., with the required accuracy of sizes being maintained. Thus internal residual strain in the lead frame member is removed. Thereafter, the linking piece 12 is removed by a trimming die appropriately. Thus the lead frame having the desired accuracy of sizes can be formed. |
