In the traditional PCB design and process, plated through holes will bring many problems. First of all, they occupy a large number of effective spaces. Secondly, a large number of plated through holes are dense, which also causes great obstacles to the wiring of the inner layer of multilayer PCB. These plated through holes take up the space needed for wiring. They pass through the surface of power and ground layer intensively, which will destroy the impedance characteristics of power ground layer and make it invalid. And the method of conventional mechanical drilling will be 20 times the workload of the blind.
In PCB design, although the size of pad and via has been gradually reduced, if the thickness of the board does not decrease proportionally, the aspect ratio of PCB through hole plating will reduce the reliability. With the development of advanced laser drilling technology and plasma dry etching technology, it is possible to apply small blind via holes and small buried holes. If the diameter of these holes is 0.3mm, the parasitic parameters will be about one-tenth of the original conventional holes, which improves the reliability of PCB.
Due to the use of blind and buried via technology, there will be few large vias on PCB, so it can provide more space for wiring. The remaining space can be used for large area shielding to improve EMI/RFI performance. At the same time, more space can also be used for the inner layer to partially shield the device and the key network cable, so that it has the best electrical performance. By using blind and buried via technology, it is more convenient to fan out the device pins, which makes the wiring of high-density pin devices (such as BGA package devices) easy, shorten the connection length, and meet the time series requirements of high-speed circuits.
All above is the characteristics and advantages of blind via hole. I hope you'll find them helpful.