42 Layer High-speed PCB

A 42-layer high-speed PCB built on R-5775G ultra-low-loss laminate, 6.3±0.3mm finished thickness, with a 0.30mm minimum mechanical drill. The high layer count and low-Df dielectric give wide signal-routing budget and stable impedance for >25Gbps SerDes channels, making the board suitable for AI training servers, switch fabrics, optical-module hosts, and 5G core network equipment. The stack manages return loss and crosstalk through dedicated reference planes and tight pressing tolerances. Sihui Fuji controls layer-to-layer registration, drill accuracy, and copper plating thickness across all 42 layers to keep impedance within ±5% and prevent skew between paired channels. Typical applications include datacenter switches, AI server backplanes, optical transport, 5G base stations, and high-end test equipment.