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I am designing a 4 layer board in which I HAVE to use blind and buried vias. This is a very dense board with (SOLID COPPER ON LAYER 4, No exceptions )

I am planning to use 1.) 1-2 microvia and 2-3 Buried vias. 2.) 1-2 and 2-3 Stacked microvias. ,

So Can you suggest whether I could go with the first configuration or I should switch to the 2nd configuration keeping cost in mind.Which configuration is cheaper.

Keep in mind that this is not HDI PCB just a mixed signal board of analog and digital

I should mention that PCB Is 0.4mm thickness. So more then 4 layers is not possible

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    \$\begingroup\$ I'd consult the manufacturer at this point, it will most likely matter how they cost the vias. \$\endgroup\$ – Voltage Spike Jun 3 at 20:54
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    \$\begingroup\$ What restricts you to choosing BBV's when there are better cost choices. Has this design been performed with DFT,DFM, DFC? \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jun 3 at 20:57
  • \$\begingroup\$ Hi, I was planning to use BBV. But can you suggest which option will be cheaper.Desgin is being done keeping. All three parameters In mind \$\endgroup\$ – Vishal Gaurav Jun 3 at 21:14
  • \$\begingroup\$ So you have no 1-4 through vias (aside from possibly ground vias)? \$\endgroup\$ – The Photon Jun 3 at 21:31
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    \$\begingroup\$ @VishalGaurav we can't tell you what's cheaper for your manufacturer. Ask your manufacturer. \$\endgroup\$ – Marcus Müller Jun 3 at 21:33
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You state this is dense board so I don't recommend using stack microvias. Since I have experience that once the vias are not align when lamination, then the board will have unexpected problem. Consider the yield rate, I guess the Manufacturer will provide the higher cost to you.

Option 1 is better choice I think. Remember once you use blind & buried vias and the quantity of blind & buried vias will not cause the higher cost. The root cause is lamination, more lamination will cause more time so the price will get higher.

However, you should ask you Manufacturer which one is benefit to you.

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I would like to suggest that your proposal to use these blind and buried vias makes for a much more expensive board. You really should look at using more than 4 layers to be able to achieve your layout whether that be 6 or 8 layers. In all likelihood the cost for such board will be cheaper than your 4 layer board with the fancy expensive vias.

More layers also lets you do a lot more with layer shielding such as multiple ground reference planes.

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  • \$\begingroup\$ Thanks, Michael for the replay. But since PCB is only 0.4mm thickness. So 4 layer is the best option I got. If you have any suggestions please do let me know \$\endgroup\$ – Vishal Gaurav Jun 4 at 5:42
  • \$\begingroup\$ I think that you are making things incredibly limited by trying to force use of a 0.4mm thick PCB. Rethink your overall system and packaging design so that you can use a thicker PCB. Then you can get more layers and eliminate the expensive fancy vias. A thicker PCB will also have other significant advantages as well. \$\endgroup\$ – Michael Karas Jun 4 at 9:09
  • \$\begingroup\$ If you are trying to package on a flex circuit then you should call it that and stop calling it a PCB. \$\endgroup\$ – Michael Karas Jun 4 at 9:09
  • \$\begingroup\$ Hello Michael This is not a flex PCB But a normal PCB Just that a thickness for 0.4mm is required. Since application is such that using 0.4mm circuit is justified \$\endgroup\$ – Vishal Gaurav Jun 4 at 9:26

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