Blind and Buried Via PCB 05

Via is an important component for multi layer PCBAs. Printed circuit boards are superimposed by copper foil circuit layer upon layer, and the connection between the different circuit layers is the via. There are three most common via are plating through hole, blind hole and buried hole.

Plating Through Hole(PTH)

PTH  is the most common via, just take up PCB and face to the light, if you can see the light, then it is the “through hole”. PTH is also the simplest kind of hole because it just need to use drill or laser light to make a full borehole.

Blind Via Hole(BVH)

Connect the outermost circuit of the PCB and the adjacent inner layer with plated through-hole, since we cannot see the opposite, so it is called “blind pass”. In order to increase the space utilization of PCB circuit layer, blind via hole came into being.

Buried Via Hole (BVH)

Buried via hole connects to any circuit layer of PCB but do not pass to the outer layer. This process cannot be done using the method of bonding after drilling, it must be in the individual circuit layer when the implementation of drilling, the first part of the internal bonding after the first plating treatment, and finally all the bonding.

You can know more clearly about the above three hole based on the below chart.