Types of PCB Vias for Customized Multilayer Circuit Boards

Customizing multi-layer circuit board PCB vias is an important link. The types of customized PCB vias are divided into three types: “blind via”, “buried via” and “through hole”. Let me introduce the three vias below. What is the difference! 　　

①Blind hole: located on the top and bottom surfaces of the circuit board, with a certain depth, used for the connection of the surface circuit and the inner circuit below, the depth of the hole and the diameter of the hole usually do not exceed a certain ratio.

②Buried hole: the connection hole located in the inner layer of the board, which does not extend to the surface layer of the PCB board. Both blind and buried holes are in the inner layer of the circuit board. Before lamination, the required through holes are drilled. After lamination, the through holes drilled before become inner holes. This situation mostly occurs in Among the multi-layer circuit boards, double-sided boards will not have this situation.

③Through hole: penetrates from the bottom of the layer to the top layer, which can be used to realize internal interconnection or as a component’s installation positioning hole. Since through holes are easier to implement in process and lower cost, generally printed circuit boards use through holes.

The application of blind vias and buried vias can reduce the size and number of layers of the circuit board to a certain extent, and at the same time improve electromagnetic compatibility, reduce customization costs, and increase product features. The wiring space occupied by through holes is very large. A dense hole will cause obstacles to the inner wiring of the multilayer circuit board. When densely passing through the surface of the electric anchor and the ground layer, it will not only destroy the impedance characteristics of the power ground layer, but also make the power ground wire Layer failure. Of course, the specific design of the vias depends on the customer’s product requirements, and not all multilayer circuit boards need to be used for blind or buried vias.