8-layer-pcb-board. PCB from 8 layer to 90 layer HDI PCB. we have made PCB over 15 years. the best samller via holes are 3 mil. the best line to line spacing are 2.1 mil. pads to pads gap are 2.2 mil.
We have many kinds PCB core. TG150, TG170,TG 180. The price will be mor echeaper about 20%.