PCBmanufacturerChina talked，as a matter of fact, most high-performance boards cannot go without blind and buried vias.So let’s learn more about them, compare them, and overview fabrication costs.

WHAT IS BLIND AND BURIED VIA IN PCB?

These are connective, plated-through holes between PCBs’ layers.They are used to route a trace between outer and internal layers.It is especially vital for multi-layered boards with complex designs where the provision of sufficient flow of both electrical and thermal current is an issue.

Vias are drilled mechanically and then plated to create an electrical connection.You can see them as simply channels that may vary in diameters/sizes and types.For example, in the image below, there is a conventional, non-optimal PTH via, a buried via, and a blind via.

It is apparent that the first type goes through the entire PCB connecting all the layers at once.But let’s focus more on the other two types as they are way more functional and complicated to use.

Blind via.Ensures a connection of the surface layer with several next ones.It is called blind because it makes it impossible to see through the PCB.

Buried via.Ensures a connection between several inner layers.It is called buried because it is not visible on a PCB’s surface.

Understanding what blind and buried via is actually is a no-brainer.But, the ways they are constructed and fabricated and the rules for their fabrication are more complex matters.

Here is an example of universal components of a via detailed in the infographics below.

· Barrel.It is the conductive pole tube that fills the pre-drilled/percolated hole.

· Pad.These are small, metallic structures that link the barrel’s ends to traces.

· Antipad.It is a round, clearance hole separating the barrel from the non-connective layer.

Regardless of the method used to fabricate a via, these elements have to be present for a connective hole to function correctly.

FPC manufacturer talk Difference Between Blind and Buried Vias

Let’s have a look at concrete factors that differentiate these types of vias:

PCB supplier China talk Advantage of blind vias:

· It saves space in other PCB layers, leaving more opportunities for routing.

· Make PCBs more functional.

· Improve the functioning of slow PCBs.

· They are the only way to optimize the use of layers in multilayer PCBs.

· It is a widespread technique, and most manufacturers offer such services.

· Minimal interference between signals.

· They ensure better pad density.

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