PCB Design – Purpose of Multiple Layer PCB Without Blind/Buried Vias

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What's the purpose of multiple layer PCBs (i.e. 4 layer,) when many manufactures like JLCPCB can't produce blind/buried vias as they just support through-vias?

Let's say I have an SMD component with a GND pad on the top layer (1st layer) and the GND plane is on the 2nd layer. What is the purpose of this 2nd layer when I am only able to connect the top layer SMD pad to the bottom layer (through-via) and not to the 2nd layer?

Somehow I am misunderstanding something since many use this kind of design with GND and VCC inner planes, but the wiring/connection from those layers to the SMD pads is something I don't get right now.

Can someone help to break my barrier?

Best Answer

I think you misunderstood the through-hole via.

Regardless of the number of layers, a through-hole via can have an electrical connection to all of the inner layers thanks to its full (not partial) inner conductive plating.

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Although the EDA you are using will isolate the via from the other inner plane(s) if the rules are set properly, you should still be careful about what the via is connected to on the other side (e.g. tracks or pads).

As for the buried and blind vias, these require multiple drilling and plating processes. But for the through-hole vias, the manufacturer stacks all the materials and layers, aligns them together, and drills only once. So there's only one drilling and plating process.