| 摘要 |
PURPOSE:To check corner parts of a lead frame to become to the starting points of concentration of stress to a sealing material after packaging, to check generation of a crack and to enhance remarkably reliability of an IC package by a method wherein after a lead frame material is blanked by etching, the corner parts of the surface thereof are processed to be beveled by the electropolishing method or the chemical polishing method. CONSTITUTION:A lead frame material consisting of a 42 alloy plate is blanked according to etching, and a glass sealed IC lead frame having 54 pins is manufactured. The lead frame thereof is dipped for 30min to be treated at 30 deg.C in a chemically abradant liquid consisting of 38wt% of sulfric acid, 17wt% of nitric acid, 10wt% of tartaric acid, and 7wt% of phosphoric acid, and the corner parts of the surface thereof is processed to be beveled. The corner parts 1, 3 formed before performance of the beveling process are formed to beveled parts 1', 3' having respectively 1.5mum of the radius of curvature after the beveling process, and the other corner parts provided with no signal expecially are beveled the same having roundness.
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