In the 1970s, multilayer PCBs began to undergo rapid development, continuously advancing toward higher precision, greater density, finer lines and smaller vias, enhanced reliability, lower costs, and automated continuous production.
Their technological evolution has progressed through a sequence ranging from single-sided boards and double-sided boards to multilayer boards, and subsequently to High-Density Interconnect (HDI) and Build-Up Multilayer (BUM) technologies. Manufacturing methods now encompass laser drilling, plasma etching, and photo-defined via formation, enabling the creation of micro-vias with diameters ranging from 0.05 to 0.15 mm. Modern UV laser drilling technology has achieved via diameters as small as 25 μm. Any-Layer Interconnect Via Hole (ALIVH) technology allows for the establishment of vertical interconnections between any two layers. Manufacturing processes have undergone continuous upgrades-such as the adoption of pinless alignment (Mass Lam) techniques, vacuum lamination, and X-ray-guided drilling-to enhance the alignment and lamination precision of multilayer boards.
Modern high-layer-count PCBs have evolved into complex, multi-layered interconnect structures comprising dozens of layers, thereby realizing a truly three-dimensional circuit architecture. Current manufacturing capabilities support minimum via diameters of 0.1 mm and minimum line widths/spacings of 0.0762 mm. To meet the demands of high-frequency and high-speed applications, dielectric materials are trending toward ultra-low-loss properties, utilizing materials such as M6 and M8 grade high-frequency/high-speed Copper-Clad Laminates (CCL), as well as high-performance resins like PPO and PTFE.
Through sustained investment in research and development, domestic enterprises have achieved significant breakthroughs in the field of high-layer-count PCBs. For instance, Yangxuan Electronics (Dongguan) Co., Ltd. was recognized as a National High-Tech Enterprise in 2024; by 2025, the company had accumulated 25 authorized patents and successfully developed a 16-layer PCB-featuring a copper thickness of 6 ounces per layer-specifically designed for power supply systems within large-scale AI data centers.
