Electronic – Blind/buried vs. through hole vias


I'm trying to learn PCB design and, from what I've read and seen, there appear to be three different types of vias:

  1. Through hole – goes all the way through the board
  2. Blind – goes from the top or bottom layer to some layer in between the top and bottom, but not all the way through
  3. Buried – is between the top and bottom layers

It seems like most semi-complex boards I've had the opportunity to look at are 4-layer boards, and that usually one layer is dedicated to GND, another to VCC, and then the other two have traces. My question is what kind of via is most appropriate when trying to connect a pad or trace from one layer to the GND or VCC layers? I ask because I would have thought that a blind or buried via should be used, but it seems like most boards I've looked at use through hole vias and that there's just a stop around the via on the layers it's not supposed to be connected to. Is there a reason to use that method instead of using a blind or buried via?

Best Answer

Blind and buried vias add a lot to the cost of a multi-layer board, and are only used on high-density, high-performance systems. The increase in cost is because the layers have to be drilled separately, assembled, and then the holes are plated. Blind vias are sometimes back-drilled (the unwanted plating is removed with a slightly larger drill from the back) which reduces the cost, as the layers are stacked before drilling.