Buried Via
What Is a Buried Via?
A buried via is a plated hole that connects two or more internal layers of a PCB without being visible on either the top or bottom surface. Because buried vias exist entirely within the board stackup, they do not consume any routing space on the outer layers — making them particularly valuable in designs where outer-layer real estate is constrained by dense component placement. Buried vias are commonly used in HDI (High Density Interconnect) boards and designs with large BGA packages that require extensive inner-layer routing.
Manufacturing buried vias requires a sequential lamination process where inner layer pairs are drilled, plated, and bonded before the full board stackup is assembled. This multi-step process increases fabrication complexity, cost, and lead time compared to boards using only through-hole vias. Designers must also consider that buried vias add constraints to the stackup design — the layers connected by buried vias must be adjacent lamination pairs, which can limit flexibility in layer assignment and signal planning.
Intelligent Via Strategy Selection
The decision to use buried vias involves complex tradeoffs between routing density, manufacturing cost, stackup flexibility, and lead time. AI-powered layout tools can quantify these tradeoffs by generating complete layouts with and without buried vias, showing engineers exactly how much routing density is gained and at what manufacturing cost. This data-driven approach to via strategy replaces the experience-based guesswork that traditionally determines whether the added complexity of buried vias is justified for a given design.






