Can i project a PCB with microvia through hole?
For Kicad yes but are there problems for the fabbrication of PCB with microvia through hole?
Usally microvia used for the near layer not through hole with 4 layers.
Ask your fabricator . . . we cannot know who you will use to make PCBs.
Cheap board houses like JLCPCB do not do micro/blind/buried vias for their prototype boards.
Anyways micro/blind/buried will significantly raise the PCB’s price.
What are you trying to do here?
If you want to make a via that goes through the whole thickness of the PCB, then it’s a regular via and not a micro via, regardless of it’s diameter. And drill diameter is just one of the parameters of a via.
There is also a limit for the minimum drill diameter, and a limit for the aspect ratio (drill diameter versus hole depth) that PCB manufactures can make.
Once I accidentally placed a microvia instead of a via on a board by using the wrong shortcut key. When I submitted for cheap fabrication it they asked: is it ok if we change this to a regular via? (Because microvia costs extra.) So I went back and discovered my mistake and resubmitted and all was good.
I understand that a question is: As via going through whole PCB thickness is regular than why KiCad allows to make it being micro via as we can see at screen shot?
IPC standards revised the definition of a microvia in 2013 to a hole with depth to diameter aspect ratio of 1:1 or less, and the hole depth not to exceed 0.25mm.
Source: Microvia - Wikipedia
Micro vias are not just small vias. It is an industry standard name for a specific result. They normally penetrate just one layer of prepreg. If they connect multiple layers of prepreg (for example connecting 3 copper layers together) then they are usually stacked. So first the via for the inner two layers is made, then a layer of prepreg + copper is added, and then another micro via is made to connect the 3rd copper layer to the first two.
If you want pictures:
So probably it’s wrong for KiCad to allow a micro via to go though the whole PCB, but it’s not among the biggest of my worries.
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