8L

parameter
Layer: 8 l
Material: fr-4 Tg170.
Plate thickness: 1.60mm
Copper thickness: 35/18/18/35um.
Line width: 3/3 mil.
Most holes: 0.2mm
Surface treatment: ENIG(1U')
Technical difficulties:
Multi-pair differential impedance control, hole to line 5.8mil.