Precisely aligned lead frame using registration traces and pads

摘要

Assemblies of aligned tape automated bonding frames on a substrate, and a method of aligning a tape automated bonding frame to connection sites on the substrate. The method includes photolithographically patterning and etching metal to form a first pattern of signal leads and a second pattern of alignment leads. A semiconductor chip is bonded to the inner lead ends of the first pattern. Metal on a substrate is photolithographically patterned and etched to provide a third pattern of substrate connection sites and a fourth pattern of registration pads. The fourth pattern of registration pads has geometric and dimensional features which precisely correspond to those of the alignment leads. Moreover, the spatial relationship of the third and fourth patterns correspond to the spatial relationship of the first and second patterns. The corresponding geometric and dimensional features of the second and fourth patterns are aligned, whereafter the registration pads and the alignment leads are soldered together. The attachment of the second and fourth patterns provide fixed registration of the first and third patterns. Preferably, the substrate includes redundant registration pads to facilitate replacement of a defective semiconductor chip.