Buried/blind vias stack up for 14 layer SoC design

Any design using B\B or microvia need to be laser drilled and the procedure remains the same whether its drilled from layer 1-2 and the rest of the vias are designed as core via which is similar to  the BB vias being stacked one above the another.

Creating a core vias reduces the burden of creating multiple BB via per layer but looses the flexibility to move around the via 

mostly these are used in higher density areas such as BGA, or when the formfactor is to small . The moment the user uses Microvias the cost of PCB fabrication also goes high. and not all the fabricators have this capability.

before designing the PCB the designer has to consult the FAB house and get the confirmation regarding the manufacturability, and get the details such as the stackup , Dielectric material being used and aspect ratio of the via , minimum trace thickness, COST etc etc.

Hope this helps... :-)

Hi Jessicak,

There is a misconception that laser drilling is required for hole sises less than 6Mil. Today it is possible for such holes to be actually drilled but not all board manufacturers support these drills and have opted to use lasers instead.
There are other processes too where by the physical pcb hole is actually etched but this depends on the laminate or substrate used. A good example of a HDI design would be something like a Intel Processor as the physical dice is
bonded to the board.

On things like dense BGA's the better option is to go with Via In Pad to open up more routing lanes. Generally speaking the golden rule is go with PTH vias if you can and then go with BB vias etc as a last resort. On designs that need
BB Vias you are going to be looking at an increase in cost & in some cases a rather large increase in cost. By way of a piece of advise if you are doing HDI designs go with plating those BB Vias shut. That is no filling of the holes
with epoxy resin which is the cheaper option.

There is no trick really. It very much depends on the size of the board and it's intended use application. On a very tight design sometimes it is better to go with a two board solution instead. That would be one board plugs into another.
In some cases this will be easier to manufacturer and also less expensive. On such designs it is probably best to choose a board house that can make such boards in-advance of a proposed layout.

Best of luck on your design.