Conducting hole (VIA) is a common type of hole used to conduct or connect copper foil circuits between conductive patterns in different layers of a circuit board. For example, blind holes or buried holes, but cannot be inserted into copper plated holes of component leads or other reinforcement materials. Because PCBs are formed by stacking and accumulating many layers of copper foil, an insulation layer is laid between each layer of copper foil, so the copper foil layers cannot communicate with each other, and their signal connections rely on through holes (via), hence the Chinese name for through holes.

The characteristic is that in order to meet the needs of customers, the conductive holes on the circuit board need to be plugged. This changes the traditional aluminum sheet plugging process by using white mesh to complete the circuit board surface solder mask and plug holes, making it stable in production, reliable in quality, and more perfect in use. Conducting holes mainly serve to connect and conduct circuits. With the rapid development of the electronics industry, higher requirements have been put forward for the production process and surface mount technology of printed circuit boards. The process of plugging through holes has been applied, and the following requirements should be met: 1. Copper is sufficient in the through hole, while solder mask can be plugged or not. 2. There must be tin and lead inside the conductive hole, with a certain thickness requirement (4um), and no solder mask ink should enter the hole, causing hidden tin beads in the hole. 3. The conductive hole must have solder mask ink plug holes, which are not transparent, and must not have tin rings, tin beads, or flatness requirements.

Blind hole: It refers to connecting the outer circuit of a PCB with adjacent inner layers through electroplated holes, which are called blind holes because the opposite side cannot be seen. At the same time, in order to increase the utilization of interlayer space in PCB circuits, blind holes are applied. That is, a conductive hole on a surface of the printed circuit board.