| 摘要 |
PURPOSE:To manufacture the lead frame, which is excellent in conductivity with a semiconductor chip, solder bondability, corrosion resistance and high temperature-resisting oxidation capacity and has durability for a prolonged term, by coating stainless steel containing chromium with nickel, a nickel-copper alloy or a nickel-tin alloy. CONSTITUTION:The content of chromium of steel containing chromium extends over 11.5-30%. It is necessary that steel containing chromium is plated with nickel, the nickel-copper alloy containing not less than 40% nickel or the nickel- tin alloy containing not less than 30% nickel in order to give the steel excellent solder bondability and high temperature-resisting oxidation capacity. When a blank to which foundation treatment is executed by polishing and wash by an acid is coated with nickel, the nickel-copper alloy or the nickel-tin alloy, excellent solder bondability is displayed when the film thickness of nickel, the nickel-copper alloy or the nickel-tin alloy is 0.1mum or more, preferably 0.2mum or more. It is preferable that the steel is plated with gold, silver or aluminum, foil is pasted or conductive paste is applied in order to improve conductivity with the semiconductor chip. |
