pcb-rnd knowledge pool
Blind/buried vias announcement
bbvia by Tibor 'Igor2' Palinkas on 2017-11-04
Tags: announcement, padstack, blind, buried, via, bbvia
Abstract: The original announcement of blind/buried vias.
Because a padstack already has to be able to look up its pad shape on a per layer group (physical layer) basis, it was sort of trivail to add blind/buried vias too.
The hole starting layer group and ending layer group is specified in a way that is transferrable between different pad stacks. The simplest thing to describe is the all-way throuh hole (needs no extra parameter). The second simplest is a blind hole (needs one parameter). A buried hole needs 2.
Following the best pcb-rnd traditions, things are not entangled: whether a padstack has a hole or not does not depend on whether it has shapes on copper or other layers. Whether a hole is plated does not depend on if it's through, blind or buried.
This gives the user maximum flexibility of combining the features, even building things that we would normally regard broken constructs, like an unplated buried hole between two inner layers, with a pad on each layer.
Again following the best pcb-rnd traditions, we are not to outsmart the user. We let the user do what the user finds useful. Later on we will provide DRC to warn for strange looking constructs, but it's the user's responsibility to use or abuse a feature.