Introduction to the types and advantages of vias in pcb

Vias are one of the important part of multilayer PCBs. From the point of view of function, vias can be divided into two categories: one is used for electrical connections between layers; the other is used for fixing or positioning devices.

From the perspective of the PCB process, these vias are generally divided into three categories, namely through hole vias, blind vias and buried vias.


through hole via: It is a common type of through hole. The through hole passes through the entire circuit board and can be used for internal interconnection or as a component installation positioning hole. Through holes are easier to identify. Just pick up the PCB and face the light, and the holes that can see the bright light are through holes.

Blind via: Connect the outermost circuit of the PCB with the adjacent inner layer by plating holes. Because the opposite side cannot be seen, it is called blind pass. It is located on the top and bottom surfaces of the PCB and has a certain depth. It is used to connect the surface line and the underlying inner line. The depth of the hole usually does not exceed a certain ratio (aperture).
 
Buried via: Refers to the connection of any circuit layer inside the PCB but not conducting to the outer layer. This process cannot be achieved by drilling after bonding. The drilling must be performed on the individual circuit layers. After the inner layer is partially bonded, it must be electroplated before it can be fully bonded. Compared with the original through holes and blind holes It takes more time, so the price is the most expensive. This process is usually only used for high-density (HDI) circuit boards to increase the usable space of other circuit layers.
 
Blind vias and buried vias are both located in the inner layer of the circuit board, and are completed by a through-hole forming process before lamination, and several inner layers may be overlapped during the formation of vias.
 
The many benefits of vias
The combination of buried, blind, and through-hole technology is also an important way to increase the density of printed circuits. Generally, buried and blind holes are tiny holes. In addition to increasing the number of wiring on the board, the buried and blind holes are interconnected by the "nearest" inner layer, which greatly reduces the number of through holes formed, and the setting of the isolation disk will also be greatly reduced. Reduce, thereby increasing the number of effective wiring and inter-layer interconnection in the board, and improving the high density of interconnection.
 
Under the same size and number of layers, a multilayer board with a combination of buried, blind, and through holes has an interconnection density that is at least three times higher than that of a conventional full through hole board. That is to say, under the same technical indicators, a circuit board with a combination of buried, blind, and through holes will greatly reduce the size of the board or reduce the number of layers of the board.
 
Therefore, buried and blind hole technologies have been increasingly used in high-density surface-mounted printed boards. Often used most often in high-density interconnect PCBs or HDIs. HDI PCB is popular because they can provide better power transmission and higher layer density. By using hidden through holes, this will also help to make the circuit board smaller and lighter, which is very useful when creating electronic products. They are commonly used in medical equipment, tablets, laptops, mobile phones and similar small electronic products.

Although blind vias and buried vias are helpful to those who need them, they can also increase the cost of the PCB. This is due to the extra work required to add them to the board, as well as the testing and manufacturing required. This means you only use them when really necessary; because you want to have a board that is both compact and efficient.

The above is an introduction to the types and advantages of vias in pcb, POE PCB Manufacturer technology can be completed as long as you need, please feel free to contact our online customer service, we are happy to serve you!