Different Types of Vias in HDI PCB

Vias are used to establish electrical connections between the layers, routes, pads, etc.If the multi-layer board is connected through the hole, the size of the PCB can be reduced, and the layer can be stacked.

4 types via are listed:

-Buried via: Connect the through holes of the inner two layers of the multi-layer HDI PCB. This through-hole is always inside the printed circuit board and cannot be seen from the outside. The buried hole is also a plating hole and requires a separate drill file.

-Through via: It is a hole that connects all layers of a multi-layer PCB from top to bottom through the PCB with a drill or laser. Through hole PCBs are easy to construct and are the most cost effective through hole type. Through holes are divided into plated through holes and non-plated through holes.

-Blind via: A hole with a drill or laser to connect the outer layer of a multi-layer high-density interconnected PCB to the inner layer. Since the hole is only visible on one side of the PCB board, it is called a blind through hole. This type of through-hole is difficult to build and expensive.

-Micro via: It is the smallest hole or diameter less than 150 microns, drilled with a laser. Microthrough-holes are most common in HDI PCBS and are often used to connect one layer of a PCB to an adjacent layer, with very small diameters compared to mechanical drilling (such as through holes). Because of their size and ability to connect one layer to an adjacent layer, they enable denser printed circuit boards to have more complex designs.