Definition

A buried via connects two or more inner layers without reaching either outer surface of the PCB. Buried vias are created by drilling and plating the sub-composite (core or build-up layers) before final lamination. They maximize routing density by allowing connections that don't consume space on outer layers. Buried vias increase manufacturing complexity and cost, as each buried via layer requires separate drilling and plating operations. Commonly used in high-layer-count boards where through-hole vias would waste routing channels.