Core Insights - The AI server design is undergoing a structural transformation, with the transition to cableless architecture and high-density interconnect (HDI) designs becoming central to the PCB industry's evolution [1][2] - The introduction of the Rubin platform marks a significant shift in PCB's role, emphasizing signal integrity and transmission stability as core design metrics [1][2] Group 1: PCB Design and Technology - The Rubin platform utilizes a cableless interconnect design, enhancing the PCB industry's status by shifting from traditional cable-based connections to multi-layer PCBs [1] - The new design materials include M8U grade for Switch Tray and M9 for Midplane, with PCB value per server increasing by over two times compared to previous generations [2] - The design logic of Rubin has become a common language in the industry, influencing other ASIC AI servers like Google TPU V7 and AWS Trainium3 [2] Group 2: Material Innovations - The demand for PCB performance in AI servers is driving significant changes in upstream materials, focusing on dielectric and thermal stability [2] - Nittobo is investing 15 billion yen to expand production of T-glass, which is expected to triple its capacity by the end of 2026, becoming a core material for ABF and BT substrates [2] - Low roughness HVLP4 copper foil is becoming mainstream due to the increasing impact of skin effect, leading to long-term supply tightness and a shift in bargaining power back to upstream material suppliers [3]