Vias are generally divided into three categories: blind vias, buried vias, and through vias.

A blind hole refers to the top and bottom surfaces of a printed circuit board. It has a certain depth and is used for the connection between the surface layer circuit and the inner layer circuit.

Buried hole refers to the connection hole located in the inner layer of the printed circuit board, and it will not extend to the surface of the circuit board.

Both types of blind and buried holes are located in the inner layer of the circuit board. Before lamination, the through-hole forming process is used to complete the process. Several inner layers may be overlapped during the formation of vias.

Through-holes, which pass through the entire circuit board, can be used to achieve internal interconnections or as mounting positioning holes for components. Because through holes are easier to implement in the process and lower in cost, they are generally used in printed circuit boards.

There are three different methods for making a blind hole plate, as described below

A. Mechanical fixed depth drilling

In the traditional multi-layer board manufacturing process, after drilling, the drilling depth is set by using a drilling machine, but this method has several problems.

a. Only one piece of diamond can be produced at a time.

b. The level of the drilling machine table is strict. The drilling depth of each spindle must be consistent. Otherwise, it is difficult to control the depth of each hole.

c. In-hole plating is difficult, especially if the depth is greater than the hole diameter, it is almost impossible to do in-hole plating.

Shenzhen Dingji Electronics Co., Ltd. is a circuit board manufacturer integrating copying, proofing, mass production, sales and service. The products include: single-sided PCB boards, double-sided PCB boards, multilayer PCB boards, impedance circuit boards, high-conductivity aluminum substrates, buried / blind-hole high-density interconnect technology (HDI) and special printed boards Mass production of circuit boards.