| 摘要 |
<p>PURPOSE:To improve accuracies of shapes and positions of inner leads by pressing a 42 alloy lead frame and then annealing for a residual stress at a high temperature for a short time. CONSTITUTION:After inner leads 2 of a lead frame 1 for a semiconductor device are plate-retained and punched, it is annealed for residual stress at a high temperature for a short time such as at 700 deg.C for 3-6min. After outer leads 4 of the frame 1 are punched by pressing, it is annealed for residual stress at a high temperature for a short time such as at 700 deg.C for 1min, and Vickers hardness of a material hardness of a burr of the lead 4 is softened to 180-220 deg.C of Vickers hardness. Thus, inner residual stresses of the inner and outer leads generated by punching can be released, and also an inner residual stress due to elongation of a guide rail 3 generated by pressing is alleviated.</p> |
