Blind and burried vias and micro vias

[georgeg]

I came across some hobbyists and they told me that, they would rather go for multi layers or micro vias than burried vias? Why is that? I also heard it is more expensive to make blind and burried vias. Why? Just curious...

 

[barry]

Blind and buried vias cost more because it takes multiple drilling and plating operations. For a through via, you just drill through all the layers at once, then you plate the vias; for blind or buried vias, you have to drill separate layers, plate those layers and then put the whole sandwich together and THEN do your through vias.

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Blind and buried vias cost more because it takes multiple drilling and plating operations. For a through via, you just drill through all the layers at once, then you plate the vias; for blind or buried vias, you have to drill separate layers, plate those layers and then put the whole sandwich together and THEN do your through vias.

 

[elle]

hi! georgeg! blind vias are connecting a inner layer to either the top or bottom layer, and the other layer is blind as it doesn't see the via. buried via is connecting two inner layers, without access to top or bottom layer. and this costs more. that is why it is a lot better to use multiple layer PCBs. I have come across a certain company which name is bittele electronics and they fabricate four layers and above PCBs. The price is reasonable.

 

[etmabreu]

Once I tried to make a 4-layer design with blind vias from layer 2 to layer 4. The manufacturer told me it was not possible to do this kind of via with the stack setup I needed.

Why is that so? How can I know which are the layers I can (or can't) connect with blind/buried vias?

 

[barry]

Once I tried to make a 4-layer design with blind vias from layer 2 to layer 4. The manufacturer told me it was not possible to do this kind of via with the stack setup I needed.

Why is that so? How can I know which are the layers I can (or can't) connect with blind/buried vias?

I think maybe you were up against a limitation of the PCB mfr. There is no fundamental reason you CAN"T do what you want. But, unless you REALLY have a shortage of real-estate on your board, blind and buried vias aren't necessary. For a four layer board, I can't believe you've got this problem. If you were working with an 8 layer or more board, then it might be an issue.

 

[etmabreu]

I think maybe you were up against a limitation of the PCB mfr. There is no fundamental reason you CAN"T do what you want. But, unless you REALLY have a shortage of real-estate on your board, blind and buried vias aren't necessary. For a four layer board, I can't believe you've got this problem. If you were working with an 8 layer or more board, then it might be an issue.

Problem is I had microstrip lines and distributed components on the top layer and I didn't wan't to "disturb" the propagation medium with via holes nearby.