Custom layer buildup
The custom layer buildup is special production. You can choose from the following cores and prepregs for a Rogers only layer construction.
For hybrid buildups or FR4-only multi
Stubs in Detail
As already mentioned, stubs interfere with the signal integrity of high-frequency circuit boards. Stubs cause unwanted resonant frequency nulls which appear in the insertion loss plo
min. thickness F (target layer);250µm;300µm;400µm;500µm
min thickness G (stub remainder);125µm;150µm;200µm;250µm
Tolerance* standard o.r.;± 100µm ± 50µm;± 100µm ± 50µm;± 100µm ± 50µm;± 100µ
Required target layer thickness "F" / stub remainder "G"
If you need a special layer buildup, please keep to the following min. layer thickness of the layer in which the drilling stops (F).
If you do not need a special layer buildup, e.g. you are using our defined layer buildups, we will do all the necessary thickness calculations regarding the thickness of "F" and “G”.
Index Type Value min.
A Plated-through via Ø 200µm
B Backdrill Ø 400µm
C Copper clearance 150µm
D Ø-Difference circumf. 100µm
E Backdrill depth 200µm
F T
The backdrill process removes stubs from plated-through-holes (vias). Stubs are the unnecessary / unused portions of vias, which extend further than the last connected inner layer. Stubs can lead to
Advantages of Backdrill
Reduced deterministic jitter Lower bit error rate (BER) Less signal attenuation with improved impedance matching Increased channel bandwidth Increased data rates Reduced EMI r
