A blind via connects an outer layer to one or more inner layers but stops partway down, so it can be seen from only one side. It is made by laser drilling, by controlled-depth mechanical drilling, or by drilling a sub-stack before the final lamination. Blind vias free routing space on the layers below and leave no stub, which is why they are common in phones and dense BGA escapes, but they add process steps and cost.
We can't fan out the 0.5 mm BGA with through vias alone, add blind vias from top to layer 2.
Also heard as
- blind via hole
- BVH
Do not mix it up with
- Buried via: A buried via connects only inner layers and cannot be seen from either surface.
Related terms
Buried via
Via that connects only inner layers and is completely hidden inside the finished board.
Microvia
Very small laser-drilled via, typically 0.15 mm or less across, spanning one thin dielectric layer.
HDI
High-density interconnect: boards built with microvias, fine lines and sequential lamination for dense parts.
Via
Plated hole that connects copper on one layer of a board to copper on another.