1, traditional plated through hole
The most common and the most expensive layer interconnect technology is the traditional plating through hole technology. In this technique, all the holes are drilled through the panel, whether or not they are the same as the hole of the pixel device or the like. The main disadvantage of this technique is that the vias should take up all the precious space of the layers without considering whether the layer is electrically connected.
2, buried hole
The buried hole is a through hole which is connected with two or more layers of a plurality of substrates.
Compared with the traditional plated through hole structure, the buried hole saves a lot of space. When the signal line density is very large, the need for more holes to connect the signal layer, but also the need for more signal routing path, the use of buried hole technology. However, because of the need for more procedural steps, the advantage of line density is to increase the cost of the circuit board.
3, blind hole
The blind hole is connected to the surface of the substrate will be plated through holes one or more layers, they are not all through the plate thickness. In the double sided multi substrate can be used on the blind hole, hole components can be connected through hole and blind hole through the circuit board. The blind hole can be in board layer stacked on each other, and can be made smaller, so it can provide more space or more signal line layout.
For SMD and for the blind hole technique is particularly useful, because they do not need large components only need a small hole, the through hole of the outer surface of the inner layer is connected with. On a very dense and thick substrate, the use of surface mount technology can reduce the weight, but also to provide designers with a full design space.