VERFAHREN ZUR HERSTELLUNG EINES PUNKTARTIG TEILWEISE BEDECKTEN ELEMENTES

摘要

A method of highly precisely and efficiently producing spot cladding members used for lead frames of semiconductor integrated circuits such as flat packages. A metal foil and a substrate member that are fed in constant steps are temporarily spot-welded successively at predetermined regular intervals by resistance welding, ultrasonic welding or laser welding, and then undesired portions are removed by laser cutting or rotary cutter. Alternatively, the metal foil fed in constant steps is cut by punching and is temporarily spot-welded onto the substrate member fed in the same manner using the punch as the welding electrode. Such a step provides a material to which pieces of metal foil of a required size are temporarily fastened maintaining a highly precise pitch. Thereafter, the constant-load control and the constant-elongation control are carried out in cascade in the steps of pressing and rolling such that the material has a predetermined thickness. Furthermore, a desired position is detected from the pitch after rolling or from a predetermined reference point to obtain the above desired load. Thus, the thickness of the material is highly precisely controlled to obtain a spot cladding member having a highly precise pitch and size.