Hi,
I am wondering whether someone can provide a detailed definition of the four Printed Circuit Board types (Blind via, micro-via technology, pad on via technology, and via). I understand these are names of different via structure in board, but if we have a substrate containing multiple types of via, which type should we use for reliability modelling?
I consulted our PCB specialist and they could only explain to me like this:
"In PCB or substrate terminology, blind via is a kind of via, it can be laser drilled via. Micro-via is also laser drilled via as we normally refer to. Pad on Via could be the IVH or mech drill via with cap." They want to see a clear definition of the PCB types so they can advise my selection here.
Thank you!
BR, Hao
Hi there,
my take on this is that:
* if you are using ONLY THT vias then choose PiTechno-pcb as "Through holes" but
* if you also have some blind holes, then chose "Blind holes" and
* so forth.
The complexity to make a PCB is greater as you go towards the "Pad on via" and what you need to understand is that "Pad on via" is ussualy comprised of a microvia + blind via or just a THT via that is then filled and capped. I would say that PCB technology identification corelates this in a way that as you can see from the table, the difference between THT and Pad on Via is ten fold. The ussual spot where you need Pad on via are high pin count footprints such as large BGA (procesors, FPGA, memory,...) and I can't immagine that a PCB designer would chose to use a THT combination with Pad on via for these components, since you inevitably close the fanout space to route inner signals out of the footprint. Therefore a more "common" microvia + blind via combo is used for pad on via and these HDI PCBs.
I would also say that if this quote (page 155 in Fides guide issue A) applies for density (PiClass definition) as "For a multilayer PCB, the layer with the highest density should be considered. The area with the highest density should be considered in any one particular layer.", why not also use it for PiTechno-pcb.
Hope this helps.