VIA, the copper foil circuit between the conductive patterns in different layers of the circuit board is conducted or connected by this hole, but the copper-plated hole of the lead leg of the component or other reinforcing materials cannot be inserted. Printed Circuit Board (PCB) is formed by stacking many copper foil layers. Copper foils can’t communicate with each other because each layer of copper foil is covered with an insulating layer, so they need via for signal link, hence the title of Chinese via.
The through hole of the circuit board must be plugged to meet the customer’s requirements. In changing the traditional aluminum plug hole process, the solder resistance and plug hole of the circuit board surface are completed by white mesh, which makes the production more stable, the quality more reliable and the application more perfect. Via holes are helpful for the interconnection of circuits. With the rapid development of electronic industry, higher requirements are put forward for the manufacturing process and surface mounting technology of printed circuit boards (PCB).
The via plugging technology came into being, and at the same time, the following requirements should be met:
1. As long as there is copper in the hole, the solder resist can be plugged or not;
2. There must be tin and lead in the hole, with a certain thickness requirement (4um), so as to prevent solder resist ink from entering the hole, resulting in tin beads hidden in the hole;
3. The via hole must be plugged with solder resist ink, opaque, free of tin rings and beads, and flat.
Blind hole is the connection between the outermost circuit of printed circuit board (PCB) and the adjacent inner layer by electroplating hole. It is called blind hole because the opposite side cannot be seen. In order to increase the utilization rate of space between circuit layers, blind holes come in handy. That is, a blind hole is a via hole to the surface of the printed board.
The blind hole is located on the top and bottom surfaces of the circuit board, and has a certain depth, which is used to connect the surface circuit with the lower inner circuit. The depth of the hole generally has a specified ratio (aperture). This manufacturing method needs special attention, and the drilling depth must be just right. If you don’t pay attention to it, electroplating in the hole will be difficult. Therefore, few factories will adopt this production method. In fact, it is also possible to make the circuit layers that need to be connected in advance drill holes in individual circuit layers first, and then glue them together, but a more precise positioning and alignment device is needed.
Buried hole is the connection between any circuit layers in the printed circuit board (PCB), but it is not connected with the outer layer, that is, there is no through hole extending to the surface of the PCB.
This manufacturing process can’t be achieved by drilling the circuit board after bonding. It is necessary to drill the individual circuit layers, first partially bonding the inner layers, then electroplating, and finally bonding them all. Because the operation process is more laborious than the original through hole and blind hole, the price is also the most expensive. This manufacturing process is usually only used for high-density circuit boards, which increases the space utilization rate of other circuit layers.
In the production process of printed circuit board (PCB), drilling is very important. The simple understanding of drilling is to drill the required via hole on the copper clad laminate, which has the function of providing electrical connection and fixing devices. If the incorrect operation leads to problems in the process of via hole, the device can’t be fixed on the circuit board, which may affect the use of the circuit board, or the whole board will be scrapped, so the process of drilling is very important.