The Eurocircuits Buildup Wizard
The buildup wizard we have developed is one of the key instruments of our “smart menus”. You can choose from
over 700 Multilayer builds, accessed by number of layers, board thickness build and copper weight. If you can use
a pre-set build you get your offer faster, the boards are easier to build and so the price is lower.
Builds also include Blind and Buried vias.
Every Multilayer build-up is constructed out of Cores, Pre-pregs and Copper Foils.
You can think of a core as a double-sided PCB. It is a rigid piece of base laminate with copper pre-bonded onto
each side. If you go to the pre-defined build-ups for a 4 layer, you will see that the standard build has a core in
the centre containing the copper tracking/planes for layers 2 (= inner layer 1) & 3 (= inner layer 2).
On each side there are one or more sheets of pre-preg and then a sheet of copper foil. Pre-preg is glass fiber
cloth pre-(im)preg(nated) with uncured resin. The sheets of pre-preg and foil are bonded onto the core using heat
and pressure. This cures the resin in the pre-preg as well as bonding the whole build. The resulting “sandwich”
is then drilled and plated like a 2-sided board. For more information on the process see our page on
We do not use depth-controlled laser drilling in our production to manufacture blind and buried vias. We use the
sequential buildup method. We first drill a core and then plate through the holes before we build and press the
stack. This process can be repeated several times. To keep the overview at a practical level and to keep costs
down, we have set forth some straightforward rules:
1. A via always has to cut through an even number of copper layers.
2. A via cannot end at the top side of a core
3. A via cannot start at the bottom side of a core
So on a standard 4-layer build, we can only drill buried vias between layers 2 & 3. If we do this, blind vias become
impossible. If you look at reversed build you will see that instead of a single core at the centre between layers 2
& 3, there are two cores on the outside of the board between layers 1 & 2 and 3 & 4. Now we can drill blind vias
between 1 & 2 and 4 & 4 but no buried vias as the dielectric between 2 & 3 is pre-preg which cannot be separately
A special build follows the same procedures but with different thicknesses at higher prices.
Asymmetrical builds are not possible. The build must be the same on either side of the centre. The main reason is
to avoid bow and twist after pressing of the PCB.
Higher layer counts work in the same way.