Advanced Substrate Technology is Ajinomoto Build-up Film and alternatives enabling fine-pitch interconnects, high-density routing, superior electrical/thermal properties — advanced substrates support next-generation packages. ABF proprietary laminate build-up process. Core glass-reinforced resin core. Build-Up Layers sequential: copper layer patterned, insulation deposited, repeat. 4-16 copper layers typical. Via-in-Pad vias directly under component pads; maximum density. Micro-Vias 20-50 μm vias via sequential lamination + drilling. Trace Pitch 40-50 μm (advanced) vs. 100 μm (standard). Layer Count modern: 6-16 copper layers vs. 4-8 older. Materials polyimide, epoxy insulation; copper traces. Impedance Control 50Ω, 100Ω differential. High-speed signal routing. Power Planes distributed throughout substrate. Low impedance. Thermal Vias dedicated vias improve die-to-PCB coupling. Loss low-loss materials (ceramic-filled organics, LTCC) for RF. CTE matched to components (~12-17 ppm/K). Tg high-Tg (>180°C) withstands lead-free reflow (>250°C). Moisture absorption affects dimensional changes. Pre-bake recommended. Manufacturing complex multi-step: lamination, drilling, patterning, plating. Cost expensive vs. FR-4 but enables higher density. Yield tight tolerances (±25 μm); yields >95%. Design Rules lithography/etching specifications; CAD enforces. RF low-loss substrates for mmWave applications. Testing ICT (in-circuit test); AOI, X-ray inspection. Advanced substrates enable next-generation packaging through dense interconnects and superior properties.