A precision vertical interconnect technology

An interconnection technology is described that utilizes excimer laser drilled vias and computer controlled plating to provide vertical (Z-axis) electrical connections in high-performance flexible circuits. Specifically, solid vias and hemispherical microcontacts are created with a 1-μm nearest-neighbor height precision for the microcontacts. An architecture with a novel structure is employed to simplify the ground plane connections for impedance controlled flex circuits. The rationale for material and unit-process selection is described. The laser drilling of holes for the vertical interconnects is outlined. The deposition of the metal interconnects is considered. The performance of the resulting structures is characterized. This technology was implemented with a polyimide substrate and nickel contacts