What is the difference between a blind and a buried via?

A blind via starts on an outer layer and stops at an inner layer, so it is visible from one side. A buried via connects inner layers only and is invisible after lamination. Blind and buried vias both require sequential lamination, which is why they cost more than through holes.

When is a microvia justified?

When the pin pitch leaves no room for a mechanical drill between pads. Laser vias of 0.1 mm allow escape routing from fine-pitch BGAs, but they add lamination cycles. Use them only where the routing needs them.

Blog

PCB Via Types Explained

A via is a hole with copper in it, but how the hole is drilled decides the stackup and the price.

Hitech Circuits Engineering Desk

Shenzhen, China · PCB fabrication and assembly

2 min read

Published: 2016-11-17

Last updated: 2026-10-18

Technical review: Process figures checked against our published capability sheet. View capability sheet

Through holes

Drilled through the whole board and plated. The default for most designs: no extra lamination, lowest cost, and the via can be used as a test point.

Drilled from an outer layer to an inner layer before the outer layers are laminated. They free routing space on the surface but add a lamination cycle.

Buried vias

Connect inner layers only. Invisible after lamination and useful in dense cores, but the most process-intensive of the mechanical options.

Microvias

Laser-drilled, 0.1 mm on our lines, usually connecting adjacent layers. They are the building block of HDI stackups and are normally filled and plated over so components can sit above them.

Choosing

Start with through holes. Move to blind or buried only when the routing will not close, and to microvias when pitch demands it. Every step up adds lamination and cost; the stackup should justify it.

Technical Specifications

Laser via: 0.1 mm minimum
Layer count: 1–38 layers
Flex / rigid-flex: up to 12 layers

Frequently Asked Questions

What is the difference between a blind and a buried via?
A blind via starts on an outer layer and stops at an inner layer, so it is visible from one side. A buried via connects inner layers only and is invisible after lamination. Blind and buried vias both require sequential lamination, which is why they cost more than through holes.
When is a microvia justified?
When the pin pitch leaves no room for a mechanical drill between pads. Laser vias of 0.1 mm allow escape routing from fine-pitch BGAs, but they add lamination cycles. Use them only where the routing needs them.

← Blog