Nanowire-based anisotropic conductive film: A low temperature, ultra-fine pitch ionterconnect solution

Advanced microelectronics packaging, driven by the multiple benefits of system performance, power, size, and cost, has now entered the three-dimensional (3-D) era. According to the International Technology Roadmap for Semiconductors 2012 [1], the interconnect pitch size is predicted to be 4-16 μm at the global interconnect level by the year 2018. Silicon die incorporated with through-silicon-via (TSV) technology [2] can be stacked using solder microbumps as high-density interconnects [3]. However, solder microbump technology faces many challenges because of the intermetallic compound growth and an underfill requirement as the bump size reduces [4]. Meanwhile, the temperature of the soldering process is more than 260 °C, which can result in high thermal stress in the devices and impact the thermal budget of the processing, particularly for the multitechnology node-stacking processes [5]. Therefore, developing interconnect methods, which can provide ultrafine-pitch capability and low-temperature process for 3-D systems, attracts continuous attention from industry [6].