How to allow microvia between two inner layers?

[JuL]

Hi, I’m routing an HDI PCB with “stacked microvia” . It’s a 8 layers PCB with microvia between L1 (top)-L2 and L2-L3. To make possible the microvia L2-L3 I create it on L1-L2 and modify manually the L1 to L3 layer.
Unfortunately the DRC add an error for each L2-L3 microvia (too many errors : more than 200 ).
Is It possible to hide those errors or allow the inner micro via?

Thanks for your support,

julien

PCBNEW release 5.1.5

[eelik]

In this way I don’t have DRC errors:

[JuL]

Hi,
With the same via’s design rules the error disappear.

I think is not “native” on PCBNEW to allow microvia between two inner layer.
Maybe on future release.

Thanks for your help.

Julien

[eelik]

Does it actually make any difference for production if you use blind/buried via instead of µvia in KiCad?

[JuL]

I going to send the project for analysis tomorrow to WE PCB. I will give you the WE answer.
For the routing it’s no natural, the micro via is allow for adjacent layer, for un blind / buried it’s only allow for L2-L7 (for an 8 layers for exemple). For the stacked via (my case) it’s another allowing. I don’t know on other software haw the stacked via are permitted.

[eelik]

These are so rare (read: expensive) technologies that virtually every time someone asks about them they are recommended to use basic technologies instead. Therefore I wouldn’t be surprised if this isn’t very mature feature in KiCad. It’s difficult to make the distinction between µ and blind/buried. Actually µvias should be blind or buried by nature because they can’t be drilled through the board, right? B/b can technically be either µ or non-µ if I’m not mistaken.

[eelik]

With quick testing it looks like it makes no different for gerber/drill output. Possibly you just have to use whatever produces the output you need and not care about the names.