Abstract: An object of this invention is to effectively prevent a progress of corrosion due to a local cell produced between a copper raw material (30) of a lead frame and a plating layer (29) on the surface, secure an anchor effect necessary for a chip loading surface without providing a palladium or palladium alloy film (29) with an excessive thickness and improve the reliability of a semiconductor device while achieving a reduction of production cost of a semiconductor device.Ground plating layers (27), (28) of multilayer structure of nickel are formed entirely on the surface of the raw material and then the palladium or palladium alloy plating layer (29) is formed on the surface thereof. A first ground plating layer (27) is formed so as to have an elaborate quality by supplying a DC current of a predetermined current value thereto as a plating current.

Abstract: An object of this invention is to effectively prevent a progress of corrosion due to a local cell produced between a copper raw material (30) of a lead frame and a plating layer (29) on the surface, secure an anchor effect necessary for a chip loading surface without providing a palladium or palladium alloy film (29) with an excessive thickness and improve the reliability of a semiconductor device while achieving a reduction of production cost of a semiconductor device.Ground plating layers (27), (28) of multilayer structure of nickel are formed entirely on the surface of the raw material and then the palladium or palladium alloy plating layer (29) is formed on the surface thereof. A first ground plating layer (27) is formed so as to have an elaborate quality by supplying a DC current of a predetermined current value thereto as a plating current.

Abstract: A contactless electrolytic polishing apparatus for manufacturing a lead frame having a smooth polished surface includes a polishing tank containing polishing solution and divided by partitions into a first cathode-containing vessel, a first solution-discharge vessel, a first anode-containing vessel, a second solution-discharge vessel, a second anode-containing vessel, a third solution-discharge vessel and a second cathode-containing vessel. A direct current is applied with ripples having a frequency of 40 to 120 Hz alternately to the anode and cathode in the electrolytic polishing tank filled with an electrolytic polishing solution so that the time for which the blank positioned between both electrodes functions as the anode may be at least 3.3 times longer than that for which it functions as the cathode. The blank is then plated with a metal by employing a customary method.

Abstract: It is an object of this invention to provide a process for manufacturing a lead frame by polishing a blank for a lead frame electrolytically and plating the electrolytically polished surface of the blank with a metal, which process enables the electrolytic polishing of the blank to be continued for a long time by employing a contactless electrolytic polishing apparatus, and can form an electrolytically polished surface which is sufficiently smooth to allow it to be plated with a very good metal coating.The contactless electrolytic polishing apparatus is employed for applying a direct current with ripples having a frequency of 40 to 120 Hz alternately to the anode and cathode in an electrolytic polishing tank filled with an electrolytic polishing solution, so that the time for which the blank positioned between both electrodes functions as the anode may be at least 3.3 times longer than that for which it functions as the cathode, and the blank is, then, plated with a metal by employing a customary method.