Development of a novel low-mass module flex PCB using nano-wire-based flip-chip interconnection

The presented study introduces a novel low-mass, flexible printed circuit board (PCB) designed for the high-density integration of silicon pixel chips, utilizing a flip-chip integration strategy. The primary aim is to develop a lightweight, compact module that ensures reliable, high-density ASIC integration while minimizing material usage. The prototype features a two-layer flexible PCB with individually powered chips, onboard de-noising capacitors, and dedicated data fan-outs. Three interconnection technologies investigated, namely Anisotropic Conductive Film (ACF), nano-wires, and gold studs — were evaluated, offering robust options for various applications. Building on the successful use of ACF for interconnection and the promising results of gold studs, which enabled full communication and data readout on a demonstrator ASIC flip-chip bonded to the novel flex, this work focuses on exploring nanowires as an innovative solution for pad-to-pad interconnection [1,2]. Nanowires offer a novel approach with the potential to enhance interconnect performance and reliability. A forceless technique is introduced to detach the flex PCB from the production carrier while preserving its integrity enabling the assembly of small structures on the detached flex. Combining flexible PCB manufacturing with advanced interconnection technologies offers a promising solution for modular, scalable detector systems and highly integrated flexible electronics.