Offset bending of curvaceously planar radiating leadframe leads in semiconductor chip packaging

摘要

A method of forming leadframes for use in manufacturing semiconductor chips starts with fabricating a plurality of leadframes by metal stamping or etching leadframe patterns into a flat ribbon of conductive material. The leadframe patterns include a plurality of outwardly radiating leads (16), inner radiating leads (15), and a central perimeter for interconnecting the outwardly and inner radiating leads. The outwardly radiating leads (16) are arranged in groups, each of which are directed along planar perpendicular coordinates. The inner radiating leads (15) have 180 degree turns in the plane of the leadframe. The inner radiating leads (15) are then successively bent at an acute angle and parallel to the plane of said leadframe so that the inner radiating leads (15) are offset from the plane of the leadframe. The bending is performed in such a manner that each of the leads are formed with a stable spring force for effective bonding to corresponding semiconductor chip pads.